podman_container: only add --volume if item not empty

Make sure the item in the list of volumes isn't empty or we can end up
with a user error where the item is '' and podman will crash with:

"host directory can not be empty"

Note that I hit that since we have some conditional volumes in THT,
where sometimes we get '' in the list of volumes. Let's handle this
case.

Change-Id: I8df1fb5d1bb72bd492e9f8e2b29dc6dae09d6b44

tripleo_ansible/ansible_plugins/modules/podman_container.py

@@ -1147,7 +1147,8 @@ class PodmanModuleParams:
 
     def addparam_volume(self, c):
         for vol in self.params['volume']:
-            c += ['--volume', vol]
+            if vol:
+                c += ['--volume', vol]
         return c
 
     def addparam_volumes_from(self, c):