Merge branch 'tb/plug-pack-bitmap-leaks'

Merge branch 'tb/plug-pack-bitmap-leaks'

Leakfix.

* tb/plug-pack-bitmap-leaks:
  pack-bitmap.c: more aggressively free in free_bitmap_index()
  pack-bitmap.c: don't leak type-level bitmaps
  midx.c: write MIDX filenames to strbuf
  builtin/multi-pack-index.c: don't leak concatenated options
  builtin/repack.c: avoid leaking child arguments
  builtin/pack-objects.c: don't leak memory via arguments
  t/helper/test-read-midx.c: free MIDX within read_midx_file()
  midx.c: don't leak MIDX from verify_midx_file
  midx.c: clean up chunkfile after reading the MIDX