Add support to start ns_server with 2i with indexer disabled
Add support to start ns_server with 2i with indexer disabled

DISABLE_2I_INDEXER flag can be used to disable indexer on a node

Change-Id: Ibed2bc07b166257035913be90e04830c10cf4f34

t3rm1n4l/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server