remote-hg: improve basic test

It appears 'let' is not present in all shells.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/remote-helpers/test-hg.sh

@@ -75,10 +75,10 @@ check_push () {
 			grep "^   [a-f0-9]*\.\.[a-f0-9]* *${branch} -> ${branch}$" error || ref_ret=1
 			;;
 		esac
-		let 'ref_ret' && echo "match for '$branch' failed" && break
+		test $ref_ret -ne 0 && echo "match for '$branch' failed" && break
 	done
 
-	if let 'expected_ret != ret || ref_ret'
+	if test $expected_ret -ne $ret -o $ref_ret -ne 0
 	then
 		return 1
 	fi