Merge branch 'maint-1.6.3' into maint

* maint-1.6.3:
Better usage string for reflog.
hg-to-git: don't import the unused popen2 module
send-email: remove debug trace
config: Keep inner whitespace verbatim

diff --cc config.c
Simple merge

diff --cc git-send-email.perl
Simple merge

diff --cc t/t1300-repo-config.sh
Simple merge