Fix wrong warning in cluster-list if no clusters and no VIMs

Change-Id: I91110bed74adc17f46d5ba425cf88661bce8a66e
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>

osmclient/sol005/cluster.py

@@ -140,7 +140,7 @@ class Cluster(GenericOSMAPIObject):
         cluster_list = self.list(filter)
         vim_list = self._client.vim.list()
         self._logger.debug(f"VIM list: {vim_list}")
-        if not vim_list:
+        if cluster_list and not vim_list:
             self._logger.warning(
                 "Could not complete cluster info with VIM account info"
             )