fix broken flush in db.network_destroy, pep8 fixes

quantum/api/faults.py

@@ -91,6 +91,7 @@ class NetworkInUse(webob.exc.HTTPClientError):
     title = 'Network in Use'
     explanation = ('Unable to remove the network: attachments still plugged.')
 
+
 class NetworkNameExists(webob.exc.HTTPClientError):
     """
     subclass of :class:`~HTTPClientError`

quantum/common/exceptions.py

@@ -107,6 +107,7 @@ class AlreadyAttached(QuantumException):
                 "%(port_id)s for network %(net_id)s. The attachment is " \
                 "already plugged into port %(att_port_id)s")
 
+
 class NetworkNameExists(QuantumException):
     message = _("Unable to set network name to %(net_name). " \
                 "Network with id %(net_id) already has this name for " \

quantum/db/api.py

@@ -89,6 +89,7 @@ def _check_duplicate_net_name(tenant_id, net_name):
         # that net-names are unique within a tenant
         pass
 
+
 def network_create(tenant_id, name):
     session = get_session()
 
@@ -126,6 +127,7 @@ def network_rename(net_id, tenant_id, new_name):
     session.flush()
     return net
 
+
 def network_destroy(net_id):
     session = get_session()
     try:
@@ -225,7 +227,7 @@ def port_unset_attachment(port_id, net_id):
     port = port_get(port_id, net_id)
     port.interface_id = None
     session.merge(port)
-    session.flush
+    session.flush()
 
 
 def port_destroy(port_id, net_id):