pollster trap error due to zero floating ip

fixes bug #1056087 when nova doesn't have any
floating ip addresses defined causes a db
exception instead of raising it should be
trapped

Change-Id: Iea441fb8bcd720339b2446525a6202941c33a1ec

ceilometer/network/floatingip.py

@@ -32,6 +32,8 @@ class FloatingIPPollster(plugin.CentralPollster):
     def get_counters(self, manager, context):
         try:
             ips = manager.resources.floating_ip_get_all(context)
+        except exception.NoFloatingIpsDefined:
+            pass
         except exception.FloatingIpNotFoundForHost:
             pass
         else: