Merge branch 'jk/config-ignore-duplicates'

Merge branch 'jk/config-ignore-duplicates'

Drop duplicate detection from "git-config --get"; this lets it
better match the internal config callbacks, which clears up some
corner cases with includes.

* jk/config-ignore-duplicates:
  builtin/config.c: Fix a sparse warning
  git-config: use git_config_with_options
  git-config: do not complain about duplicate entries
  git-config: collect values instead of immediately printing
  git-config: fix regexp memory leaks on error conditions
  git-config: remove memory leak of key regexp
  t1300: test "git config --get-all" more thoroughly
  t1300: remove redundant test
  t1300: style updates