Separate pretty-printing commit message (comment) into git_print_log
and git_print_simplified_log subroutines. As of now the former is used
in git_commit, the latter in git_log and git_commitdiff.
Signed-off-by: Jakub Narebski <jnareb@gmail.com> Signed-off-by: Junio C Hamano <junkio@cox.net>