LBaaS: fix handling pending create/update members and health monitors

When agent requests loadbalancer logical config from server,
server returns only active pool members and health_monitors.
Need to make server return also members and monitors which are in pending states.

Also a small refactoring moving ACTIVE_PENDING set to common place

Change-Id: I8e10004f199f982b055da18ea7a0e5e4d11fa7fb
Closes-Bug: #1259965
Expunge session contents between plugin requests

In the NVP plugin, metadata processing performs several plugin operations
with the same context (and db session). The first operation might leave
persisted objects in the session instance which then conflict with objects
created in the second operation.

Closes-Bug: #1266482

Change-Id: Ic9e2b952013610647aa222f1a8b6e33504b54b37
Configure floating IPs addresses after NAT rules

Change the behaviour of the L3 agent in order to set the IP addresses
for the floating IPs on the external gateway interface after the
relevant NAT rules have been applied.
This will avoid a transitory period in which the floating IP exists
and is reachable but it not yet wired to the actual target.

Partial-Bug: #1265505

Change-Id: Ib382fde021868bab2185f2fa5bdee86559148ba7
Fix error message typo

 * Fix error message typo in "_network_admin_state"
   function where "Network Admin State Validation Falied"
   should be changed to "Network Admin State Validation Failed"

Change-Id: I767e93c300250b4422e3980f799862ceb976c951
Closes-Bug: #1276409
Signed-off-by: Fawad Khaliq <fawad@plumgrid.com>
Imported Translations from Transifex

Change-Id: I05e158928b76ba1d8aeb1b74fcf07035e419825d
Merge "Configure floating IPs addresses after NAT rules"
Merge "Fix error message typo"
Merge "Expunge session contents between plugin requests"
Merge "LBaaS: fix handling pending create/update members and health monitors"
Merge "Imported Translations from Transifex"