fixes CC-593: remove vhosts from global vhosts when its service is removed

https://jira.zenoss.com/browse/CC-593

![cc-593-1a](https://cloud.githubusercontent.com/assets/2837923/5422786/7d102a5c-825b-11e4-902e-8d492e43adee.png)
![cc-593-1b](https://cloud.githubusercontent.com/assets/2837923/5422789/7d1fa77a-825b-11e4-8840-98711ccb887a.png)
![cc-593-1c](https://cloud.githubusercontent.com/assets/2837923/5422791/7d239b3c-825b-11e4-8c63-46c46222ed95.png)
![cc-593-1d](https://cloud.githubusercontent.com/assets/2837923/5422788/7d1e8bd8-825b-11e4-88de-3503a967c783.png)
![cc-593-3a](https://cloud.githubusercontent.com/assets/2837923/5422787/7d1ce1ac-825b-11e4-84eb-9bd259d4a748.png)

Step 4:
```
{noformat}
# plu@plu-9: serviced service status centralquery
NAME			ID				STATUS		UPTIME		HOST	IN_SYNC		DOCKER_ID
└─Zenoss.core		cm64du6v7v0wgojzhblblqnw6	Running		3m8.297343602s	plu-9	Y		f86c480249b2
  └─CentralQuery	9hjtyqgud7tnydjt8ul3ut4hq	Running		3m8.878245914s	plu-9	Y		88e3a162aa45

# plu@plu-9: serviced service stop centralquery
Scheduled 1 service(s) to stop

# plu@plu-9: serviced service status centralquery
NAME			ID				STATUS		UPTIME			HOST	IN_SYNC		DOCKER_ID
└─Zenoss.core		cm64du6v7v0wgojzhblblqnw6	Running		3m22.411124253s		plu-9	Y		f86c480249b2
  └─CentralQuery	9hjtyqgud7tnydjt8ul3ut4hq	Stopped								
```

Step 5:
```
{noformat}
# plu@plu-9: serviced service remove centralquery
9hjtyqgud7tnydjt8ul3ut4hq

# plu@plu-9: serviced service status centralquery
service not found
```

![cc-593-6-expected](https://cloud.githubusercontent.com/assets/2837923/5422790/7d20095e-825b-11e4-980a-79ad5e83cee3.png)