Update git submodules

* Update docs/submodules/music.git from branch 'master'
  to 99f396136789182931fbded1127856247593d91b
  - Remove key.properties
    
    Issue-ID: MUSIC-582
    Signed-off-by: Tschaen, Brendan <ctschaen@att.com>
    Change-Id: I52cbc8399a27006f70db2f8f4dff4dc09856d9da
    
1 file changed