The check that the source is ahead of the destination incorrectly expects
pop_most_recent_commit() to gracefully handle an empty list.
Fix by just checking the list itself, rather than the return value of the
pop function.
[jc: I did the test script that demonstrated the problem]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
