NSX: Avoid floating IP status reset

The method for setting the floating IP status in the NSX plugin
has a flaw that causes in some cases the status to be reset.
This patch removes this bug and also protects against regression
adding status check in the unit test covering floating ip
creation.

This patch also moves the above mentioned unit test in a more
suitable place in the test same module.

Change-Id: Ib08c421ade20ce23b5c08145203a2df6a8f3efa5
Closes-Bug: #1357514
Join tables in query for down L3 agents

Join the agent table together with the L3 agent scheduler
table. This fixes an issue where the query would return
all admin_state_up L3 agents with router bindings when
any agent in the database was dead (missed heartbeats)
instead of just returning the dead L3 agents with bindings.

Closes-Bug: #1359460
Change-Id: I29215f81be7e3513155faaad015e24dbf1a1ad5d
Merge "NSX: Avoid floating IP status reset"
Merge "Join tables in query for down L3 agents"