Update test based on change to assert package.

Change-Id: I28ec240e9a811500a708bc1b6f76dd9c190b74f1
Reviewed-on: https://skia-review.googlesource.com/18033
Reviewed-by: Ravi Mistry <rmistry@google.com>
Commit-Queue: Ben Wagner <benjaminwagner@google.com>
diff --git a/go/mockhttpclient/muxclient_test.go b/go/mockhttpclient/muxclient_test.go
index b0da22a..ea1c874 100644
--- a/go/mockhttpclient/muxclient_test.go
+++ b/go/mockhttpclient/muxclient_test.go
@@ -80,7 +80,7 @@
 	assert.Contains(t, err.Error(), "while handling HTTP request for http://example.com/add/foo?name=bar&size=42")
 
 	assert.Equal(t, 1, len(mockT.errors))
-	re := regexp.MustCompile(`Not equal:\s+expected: "foo"\s+received: "bar"`)
+	re := regexp.MustCompile(`Not equal:\s+expected: "foo"\s+actual: "bar"`)
 	assert.True(t, re.MatchString(mockT.errors[0]), "Expected test failure message to match regexp %q, but got %q", re, mockT.errors[0])
 }