Cleanup uninitialized value in chomp

which happens if you use ActiveState Perl and a
pipe workaround specially for it.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/perl/Git.pm b/perl/Git.pm
index 2f6b59a..c1729ba 100644
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -275,7 +275,7 @@
 
 	} else {
 		my @lines = <$fh>;
-		chomp @lines;
+		defined and chomp for @lines;
 		try {
 			_cmd_close($fh, $ctx);
 		} catch Git::Error::Command with {