Update git submodules

* Update docs/submodules/appc.git from branch 'master'
  to 51550d6c0e25f0e620f3ec7efe078185a85d8e26
  - Replaced equals with equalsIgnoreCase method
    
    Sonar fix
    
    Issue-ID: APPC-1546
    Change-Id: I27ca1efc97240419f206502860b63d8e625c0bf8
    Signed-off-by: Jegadeesh Babu <jegabab1@in.ibm.com>
    
1 file changed