Deleting a VDB from inventory does not remove it

Using JON 2.4, deleting a VDB through JON GUI inventory removes the vdb from
the EDS instance, but does not remove it from inventory. Instead, it shows the
vdb as unavailable.

How reproducible:

Steps to Reproduce:
1. Deploy a vdb to EDS
2. Have agent report vdb to JON, verify in GUI
3. In JON inventory, delete the vdb

Actual results:
VDB is removed from physical server but remains in JON inventory, just as
disabled. It remains there even after running 'discovery -f' from the agent
console.

Expected results:
VDB is removed from physical server and removed from JON inventory.

Additional info:
https://bugzilla.redhat.com/show_bug.cgi?id=739789