Delete undeclared variable in guest-agent API class

The commit c7d93e7ce7 (not linked to
a gerrit review) introduced a local variable "timeout", used in a
 method of the API class

The review I9ad1b441eca855a4304454014ae746ec51bef8f3 deleted the
declaration of this variable but did not remove where it was used
in the class.

This patch removes the unused variable.

Closes-Bug: #1332333
Change-Id: Ie7aa66ceeca4efe63d91d60bcedb760ec181d443

trove/guestagent/api.py

@@ -59,11 +59,8 @@ class API(proxy.RpcProxy):
         except Exception as e:
             LOG.error(e)
             raise exception.GuestError(original_message=str(e))
-        except Timeout as t:
-            if t is not timeout:
-                raise
-            else:
-                raise exception.GuestTimeout()
+        except Timeout:
+            raise exception.GuestTimeout()
 
     def _cast(self, method_name, **kwargs):
         LOG.debug("Casting %s" % method_name)