clone: correctly report http_fetch errors

The exit status from curl was accidentally lost by the
'case' statement. We need to explicitly save it so that $?
doesn't get overwritten.

This improves the error message when fetching from an http
repository which has never had update-server-info run.
Previously, it would fail to note the fetch error and
produce multiple errors about the lack of origin branches.
It now correctly suggests running git-update-server-info.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-clone.sh

@@ -35,11 +35,12 @@ fi
 
 http_fetch () {
 	# $1 = Remote, $2 = Local
-	curl -nsfL $curl_extra_args "$1" >"$2" ||
-		case $? in
-		126|127) exit ;;
-		*)	 return $? ;;
-		esac
+	curl -nsfL $curl_extra_args "$1" >"$2"
+	curl_exit_status=$?
+	case $curl_exit_status in
+	126|127) exit ;;
+	*)	 return $curl_exit_status ;;
+	esac
 }
 
 clone_dumb_http () {