Remove call to deprecated method in tempest

Fix below warning:
"Use of: 'verify-tempest-config' is deprecated, please use: 'tempest verify-config'"

Change-Id: If66096cde31fedda407e1e6ac6899b196569a454

Author: Gang Wei

lib/tempest

@@ -325,7 +325,7 @@ function configure_tempest {
     local tmp_cfg_file
     tmp_cfg_file=$(mktemp)
     cd $TEMPEST_DIR
-    tox -revenv -- verify-tempest-config -uro $tmp_cfg_file
+    tox -revenv -- tempest verify-config -uro $tmp_cfg_file
 
     local compute_api_extensions=${COMPUTE_API_EXTENSIONS:-"all"}
     if [[ ! -z "$DISABLE_COMPUTE_API_EXTENSIONS" ]]; then