git-svn: cleanup: factor out longest_common_path() function

I hadn't looked at this code in a while and had to read this
again to figure out what it did.  To avoid having to do this
again in the future, I just gave gave the hunk a descriptive
name.
Signed-off-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-svn.perl

@@ -3072,11 +3072,8 @@ sub gs_do_switch {
 	$editor->{git_commit_ok};
 }
 
-sub gs_fetch_loop_common {
-	my ($self, $base, $head, $gsv, $globs) = @_;
-	return if ($base > $head);
-	my $inc = $_log_window_size;
-	my ($min, $max) = ($base, $head < $base + $inc ? $head : $base + $inc);
+sub longest_common_path {
+	my ($gsv, $globs) = @_;
 	my %common;
 	my $common_max = scalar @$gsv;
 
@@ -3108,6 +3105,15 @@ sub gs_fetch_loop_common {
 			last;
 		}
 	}
+	$longest_path;
+}
+
+sub gs_fetch_loop_common {
+	my ($self, $base, $head, $gsv, $globs) = @_;
+	return if ($base > $head);
+	my $inc = $_log_window_size;
+	my ($min, $max) = ($base, $head < $base + $inc ? $head : $base + $inc);
+	my $longest_path = longest_common_path($gsv, $globs);
 	while (1) {
 		my %revs;
 		my $err;