Fix upgrade test (#5021)

A conflict between #4911 and #4737 caused unit test to be broken.

#4737 added a new test to `upgrade_test.go` and the changes in
#4911 updated all of these test to ignore differences in the config
overrides secret.  Since these two PRs merged in parallel, the new
test was missing this update.

Update the new test to also ignore differences in the config overrides
secret as the other ones do.

Signed-off-by: Alex Leong <alex@buoyant.io>

cli/cmd/upgrade_test.go

@@ -390,6 +390,9 @@ func TestUpgradeWebhookCrtsNameChange(t *testing.T) {
 	expectedManifests := parseManifestList(expected)
 	upgradeManifests := parseManifestList(upgrade.String())
 	for id, diffs := range diffManifestLists(expectedManifests, upgradeManifests) {
+		if id == overridesSecret {
+			continue
+		}
 		for _, diff := range diffs {
 			t.Errorf("Unexpected diff in %s:\n%s", id, diff.String())
 		}