Only fall back to email search if the "nickname" has an @ character. …

…This is because email searches will not go through the cache, so should be avoided if possible.

security/nss/lib/pk11wrap/pk11cert.c

@@ -1280,7 +1280,9 @@ PK11_FindCertFromNickname(char *nickname, void *wincx) {
 	nssPKIObjectCollection_AddInstances(collection, instances, 0);
 	nss_ZFreeIf(instances);
 	/* if it wasn't found, repeat the process for email address */
-	if (nssPKIObjectCollection_Count(collection) == 0) {
+	if (nssPKIObjectCollection_Count(collection) == 0 &&
+	    PORT_Strchr(nickname, '@') != NULL) 
+	{
 	    (void)nssTrustDomain_GetCertsForEmailAddressFromCache(defaultTD, 
 	                                                          nickname, 
 	                                                          certList);