Regression fix: not purged object is not purged after 'purge --local'

call_action -> self.setup_environ -> os.environ['OPENSVC_SVC_ID'] = self.id -> create object if object is absent and not self.volatile

So after purge/delete action the object is recreated

The regression was introduced by #817b97660894971e18689393c6090d1a57a901c6

Reproduce bug with:
   om foo create
   om foo purge --local
   om foo ls

opensvc/core/objects/svc.py

@@ -730,6 +730,12 @@ def freezer(self):
 
     @lazy
     def id(self):
+        """
+        return object id:
+        When object has no id a new id is created and if object is not volatile
+        the object config file is updated.
+        id should not be called on deleted object else new empty object will be created
+        """
         try:
             return self.conf_get("DEFAULT", "id")
         except ex.OptNotFound as exc:
@@ -1793,7 +1799,11 @@ def restore():
             os.environ.update(prev_env)
         os.environ['OPENSVC_SVCPATH'] = self.path
         os.environ['OPENSVC_SVCNAME'] = self.name
-        os.environ['OPENSVC_SVC_ID'] = self.id
+        try:
+            os.environ['OPENSVC_SVC_ID'] = self.conf_get("DEFAULT", "id")
+        except:
+            # don't call self.id (to avoid create object side effect when object is deleted)
+            pass
         os.environ['OPENSVC_KIND'] = self.kind
         if self.namespace:
             os.environ['OPENSVC_NAMESPACE'] = self.namespace