skip merges

git log --follow seems to sometimes show merges from before the file was
ever created. So, skip them, a file shouldn't be first created during a
merge anyway.

IkiWiki/Plugin/git.pm

@@ -613,7 +613,8 @@ sub rcs_getctime ($) {
 	# Remove srcdir prefix
 	$file =~ s/^\Q$config{srcdir}\E\/?//;
 
-	my @raw_lines = run_or_die('git', 'log', '--follow',
+	my @raw_lines = run_or_die('git', 'log', 
+		'--follow', '--no-merges',
 		'--pretty=raw', '--raw', '--abbrev=40', '--always', '-c',
 		'-r', '--', $file);
 	my @ci;