Update git submodules

Update git submodules

* Update docs/submodules/appc.git from branch 'master'
  to 6898b8cfb815892115c86f80d85edd895a1292a3
  - APPC-1652- Removing Duplicate import

    Unused and useless imports should not occur if that is the case.

    Leaving them in reduces the code's readability, since their presence can be confusing.

    Issue-ID: APPC-1652
    Change-Id: I64e50083b9b0fe40fa0ba32723e30adb0dbce08e
    Signed-off-by: Dasari Anusha <danush10@in.ibm.com>
    Signed-off-by: anushadasari <danush10@in.ibm.com>
    Change-Id: I1ddafa429afb23a0eb6cb120a20a774ff9a032b8