Revert "Fix todo that is not needed anymore stestr conf"

This reverts commit 35d94fd6093edfb80283d43e819bcba7c75bedbf.

Removing the try except makes tempest not stable branch invariant and break backports.
this fixes that

Change-Id: Ib78ca25ff25addd4c19716e59f6e638dabdc7054

.stestr.conf

@@ -1,3 +1,3 @@
 [DEFAULT]
-test_path=mistral_tempest_tests
+test_path=./mistral-tempest-plugin/tests
 top_dir=./

mistral_tempest_tests/services/base.py

@@ -81,11 +81,16 @@ class MistralClientBase(rest_client.RestClient):
 
     def delete_obj(self, obj, name, force=None):
         if force:
+            # TODO(apetrich) This try except is a partial implementation
+            # to be removed once force deletion lands in mistral
+            try:
                 return self.delete('{obj}/{name}?force={force}'.format(
                     obj=obj,
                     name=name,
                     force=bool(force))
                 )
+            except Exception:
+                pass
 
         return self.delete('{obj}/{name}'.format(obj=obj, name=name))