Update git submodules

* Update docs/submodules/music.git from branch 'master'
  to 84ca96a175ba40f0dced5845cdd28f925ec3fd97
  - Remove unused Dockerfile
    
    Issue-ID: MUSIC-574
    Signed-off-by: Tschaen, Brendan <ctschaen@att.com>
    Change-Id: Ib375fc16bcc88b785bb3a9983b26156d42a65faf
    
1 file changed