vcs-svn: Check for errors from open()

test-svn-fe segfaults when passed a bogus path.  Simplify debugging by
exiting with a meaningful error message instead.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/svn-fe/svn-fe.c

@@ -8,7 +8,8 @@
 
 int main(int argc, char **argv)
 {
-	svndump_init(NULL);
+	if (svndump_init(NULL))
+		return 1;
 	svndump_read((argc > 1) ? argv[1] : NULL);
 	svndump_deinit();
 	svndump_reset();