TortoiseGitMerge: Fix background of the info label in the find dialog

Based on TortoiseSVN revision 25364, 25366

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Fixed issue #2147: Resolve not dealing correctly with (modify/delete) conflicts

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>