Update git submodules

* Update docs/submodules/msb/discovery.git from branch 'master'
  to a900b81fc5a962c5037f485960dbeea70311154f
  - fix maven-dockera-stage build error
    
    Issue-ID: MSB-373
    Signed-off-by: Huabing Zhao <zhao.huabing@zte.com.cn>
    Change-Id: I570361b1e646fab8f9abbfc770ddb6ba3d05cca4
    
1 file changed