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