Update git submodules

* Update docs/submodules/usecase-ui.git from branch 'master'
  to c50f96c8914ba6a5153d81a600eb3bb8073a431d
  - Merge "Support OTN Domain Management"
  - Support OTN Domain Management
    
    Change-Id: I4e431e642c1f0ec1d998614f861ee0909c1c5ffe
    Issue-ID: USECASEUI-226
    Signed-off-by: guochuyicmri <guochuyi@chinamobile.com>
    
1 file changed