git-svn: clone: Fail on missing url argument

cmd_clone should detect a missing $url arg before using it otherwise
an uninitialized value error is emitted in even the simplest case of
'git svn clone' without arguments.

Signed-off-by: Christopher Layne <clayne@anodized.com>
Signed-off-by: Eric Wong <e@80x24.org>

git-svn.perl

@@ -507,7 +507,10 @@ sub init_subdir {
 
 sub cmd_clone {
 	my ($url, $path) = @_;
-	if (!defined $path &&
+	if (!$url) {
+		die "SVN repository location required ",
+		    "as a command-line argument\n";
+	} elsif (!defined $path &&
 	    (defined $_trunk || @_branches || @_tags ||
 	     defined $_stdlayout) &&
 	    $url !~ m#^[a-z\+]+://#) {