Fix for nailgun in setup.py

Packaged nailgun module is lowercase, however in setup.py its Nailgun
 this prevents being able to use 'python setup.py develop' which is needed
 for development envs

Closes-bug: #1272552

Change-Id: If255757012cf21542b6b0803d9fb30f757f915f8
Merge "Fix for nailgun in setup.py"