Update git submodules

Update git submodules

* Update docs/submodules/appc.git from branch 'master'
  to 1843caa854f58b133e2c97e5d75a4705f2942280
  - Feature for micro service communication

    The appc-service-communicator feature will be responsible
    for communication between any appc microservices which are
    developed.

    The appc dmaap micro service connector is part of this feature.
    MessagingConnector.java is the main new class here.

    Some code is copied from appc event listener and dmaap adapter.
    Will be moved in a later commit.

    Change-Id: Ic57f5ee6a9ab1538c6ddaa3e7c25ac0c9797fae0
    Signed-off-by: Patrick Brady <patrick.brady@att.com>
    Issue-ID: APPC-1744