xenapi: Drop check for auth

Since they are done inside virAuthGetPassword and virAuthGetUsername
when needed. Also, only auth is checked, but auth->cb, which that could
lead to a crash if the callback is NULL.
Signed-off-by: NMarcos Paulo de Souza <marcos.souza.org@gmail.com>

src/xenapi/xenapi_driver.c

@@ -152,12 +152,6 @@ xenapiConnectOpen(virConnectPtr conn, virConnectAuthPtr auth,
         goto error;
     }
 
-    if (auth == NULL) {
-        xenapiSessionErrorHandler(conn, VIR_ERR_AUTH_FAILED,
-                                  _("Authentication Credentials not found"));
-        goto error;
-    }
-
     if (conn->uri->user != NULL) {
         if (VIR_STRDUP(username, conn->uri->user) < 0)
             goto error;