Update git submodules

* Update docs/submodules/appc.git from branch 'master'
  to c1decc814fb7c646399df2b2d94c65c695190f97
  - Increment version to 1.6.4-SNAPSHOT
    
    Change-Id: I0dfdd848265f21e1584903ea14aa4df6d08a2f94
    Signed-off-by: Patrick Brady <patrick.brady@att.com>
    Issue-ID: APPC-1686
    
1 file changed