Remove wrong reference to object attribute in nvplib

Plus, added negative tests that were not covering the
exception handling bits.

Fixes bug #1189730

Change-Id: I5df914c6b748a03816217336431c2b0b597481b5
Rename agent_loadbalancer directory to loadbalancer

Rename agent_loadbalancer directory to loadbalancer. and move
plugings/services directory one level up.
Fix tests and imports accordingly

fixes bug 1179276

Change-Id: If9e027b00824d612dfdd03e47efa9c08e419f205
Merge "Rename agent_loadbalancer directory to loadbalancer"
Merge "Remove wrong reference to object attribute in nvplib"