Add NVP advanced service check before deleting a router

Since NVP advanced services(LB/FW/VPN) are all routed inserted,
it is necessary to check service in use before deleting a router.
    *If there is one service inserted into the router, it would raise
RouterInUseByXXService error when deleting the router.

Change-Id: I9844f53918cad17cafde0783fe6b69cff246791d
Close-Bug: #1295494
NSX: Fix request_id in api_client to increment

Previously, the NSX request_id in the api_client would always be
0 because the current request id was stored in the class which is
always initialized on each request. This patch fixes that by storing
the request_id as a class variable.

Change-Id: I9ff4d3eb09899fe6d14b462dddf9daddbf77873b
Closes-bug: 1325100
Merge "NSX: Fix request_id in api_client to increment"
Merge "Add NVP advanced service check before deleting a router"