Removed RPC get-node-ip-address from flow-node-inventory

this RPC is not needed. IP address is stored in datastore.
Removing of implementation should be merged first:
	https://git.opendaylight.org/gerrit/#/c/10382/

Change-Id: I749a65edf2a774d3a91cb210eb9bc9189a983e45
Signed-off-by: Martin Sunal <msunal@cisco.com>