builtin/mv: free or UNLEAK multiple pointers at end of cmd_mv

builtin/mv: free or UNLEAK multiple pointers at end of cmd_mv

These leaks all happen at the end of cmd_mv, hence don't matter in any
way. But we still fix the easy ones and squash the rest to get us closer
to being able to run tests without leaks.

LSAN output from t0050:

Direct leak of 384 byte(s) in 1 object(s) allocated from:
    #0 0x49ab49 in realloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
    #1 0xa8c015 in xrealloc wrapper.c:126:8
    #2 0xa0a7e1 in add_entry string-list.c:44:2
    #3 0xa0a7e1 in string_list_insert string-list.c:58:14
    #4 0x5dac03 in cmd_mv builtin/mv.c:248:4
    #5 0x4ce83e in run_builtin git.c:475:11
    #6 0x4ccafe in handle_builtin git.c:729:3
    #7 0x4cb01c in run_argv git.c:818:4
    #8 0x4cb01c in cmd_main git.c:949:19
    #9 0x6bd9ad in main common-main.c:52:11
    #10 0x7fbfeffc4349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Direct leak of 16 byte(s) in 1 object(s) allocated from:
    #0 0x49a82d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
    #1 0xa8bd09 in do_xmalloc wrapper.c:41:8
    #2 0x5dbc34 in internal_prefix_pathspec builtin/mv.c:32:2
    #3 0x5da575 in cmd_mv builtin/mv.c:158:14
    #4 0x4ce83e in run_builtin git.c:475:11
    #5 0x4ccafe in handle_builtin git.c:729:3
    #6 0x4cb01c in run_argv git.c:818:4
    #7 0x4cb01c in cmd_main git.c:949:19
    #8 0x6bd9ad in main common-main.c:52:11
    #9 0x7fbfeffc4349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Direct leak of 16 byte(s) in 1 object(s) allocated from:
    #0 0x49a82d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
    #1 0xa8bd09 in do_xmalloc wrapper.c:41:8
    #2 0x5dbc34 in internal_prefix_pathspec builtin/mv.c:32:2
    #3 0x5da4e4 in cmd_mv builtin/mv.c:148:11
    #4 0x4ce83e in run_builtin git.c:475:11
    #5 0x4ccafe in handle_builtin git.c:729:3
    #6 0x4cb01c in run_argv git.c:818:4
    #7 0x4cb01c in cmd_main git.c:949:19
    #8 0x6bd9ad in main common-main.c:52:11
    #9 0x7fbfeffc4349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Direct leak of 8 byte(s) in 1 object(s) allocated from:
    #0 0x49a9a2 in calloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
    #1 0xa8c119 in xcalloc wrapper.c:140:8
    #2 0x5da585 in cmd_mv builtin/mv.c:159:22
    #3 0x4ce83e in run_builtin git.c:475:11
    #4 0x4ccafe in handle_builtin git.c:729:3
    #5 0x4cb01c in run_argv git.c:818:4
    #6 0x4cb01c in cmd_main git.c:949:19
    #7 0x6bd9ad in main common-main.c:52:11
    #8 0x7fbfeffc4349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Direct leak of 4 byte(s) in 1 object(s) allocated from:
    #0 0x49a9a2 in calloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
    #1 0xa8c119 in xcalloc wrapper.c:140:8
    #2 0x5da4f8 in cmd_mv builtin/mv.c:149:10
    #3 0x4ce83e in run_builtin git.c:475:11
    #4 0x4ccafe in handle_builtin git.c:729:3
    #5 0x4cb01c in run_argv git.c:818:4
    #6 0x4cb01c in cmd_main git.c:949:19
    #7 0x6bd9ad in main common-main.c:52:11
    #8 0x7fbfeffc4349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Indirect leak of 65 byte(s) in 1 object(s) allocated from:
    #0 0x49ab49 in realloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
    #1 0xa8c015 in xrealloc wrapper.c:126:8
    #2 0xa00226 in strbuf_grow strbuf.c:98:2
    #3 0xa00226 in strbuf_vaddf strbuf.c:394:3
    #4 0xa065c7 in xstrvfmt strbuf.c:981:2
    #5 0xa065c7 in xstrfmt strbuf.c:991:8
    #6 0x9e7ce7 in prefix_path_gently setup.c:115:15
    #7 0x9e7fa6 in prefix_path setup.c:128:12
    #8 0x5dbdbf in internal_prefix_pathspec builtin/mv.c:55:23
    #9 0x5da575 in cmd_mv builtin/mv.c:158:14
    #10 0x4ce83e in run_builtin git.c:475:11
    #11 0x4ccafe in handle_builtin git.c:729:3
    #12 0x4cb01c in run_argv git.c:818:4
    #13 0x4cb01c in cmd_main git.c:949:19
    #14 0x6bd9ad in main common-main.c:52:11
    #15 0x7fbfeffc4349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Indirect leak of 65 byte(s) in 1 object(s) allocated from:
    #0 0x49ab49 in realloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
    #1 0xa8c015 in xrealloc wrapper.c:126:8
    #2 0xa00226 in strbuf_grow strbuf.c:98:2
    #3 0xa00226 in strbuf_vaddf strbuf.c:394:3
    #4 0xa065c7 in xstrvfmt strbuf.c:981:2
    #5 0xa065c7 in xstrfmt strbuf.c:991:8
    #6 0x9e7ce7 in prefix_path_gently setup.c:115:15
    #7 0x9e7fa6 in prefix_path setup.c:128:12
    #8 0x5dbdbf in internal_prefix_pathspec builtin/mv.c:55:23
    #9 0x5da4e4 in cmd_mv builtin/mv.c:148:11
    #10 0x4ce83e in run_builtin git.c:475:11
    #11 0x4ccafe in handle_builtin git.c:729:3
    #12 0x4cb01c in run_argv git.c:818:4
    #13 0x4cb01c in cmd_main git.c:949:19
    #14 0x6bd9ad in main common-main.c:52:11
    #15 0x7fbfeffc4349 in __libc_start_main (/lib64/libc.so.6+0x24349)

SUMMARY: AddressSanitizer: 558 byte(s) leaked in 7 allocation(s).

Signed-off-by: Andrzej Hunt <andrzej@ahunt.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>