Fix segment allocation tables in Cisco N1kv plugin

The segment allocation table is emptied on deleting any network profile.
This change allows the use of segment range from the network profile table.
By using the network profile UUID as a foreign key in the segment allocations table,
tables are cleaned up only for the segments associated with
the deleted network profile via CASCADE, leaving no inconsistencies.

Change-Id: I507041fac3768a7b688ddcf28c4d97c618bfe3f9
Closes-Bug: #1288407
Merge "Fix segment allocation tables in Cisco N1kv plugin"