Update git submodules

* Update docs/submodules/usecase-ui.git from branch 'master'
  to 2eb611bcb3d776714f15a47e32b8ac77861d31cd
  - Merge "add usecase-ui user guide"
  - add usecase-ui user guide
    
    Change-Id: I97155072f9cf212ce6a2155bd07a6c57546222e5
    Issue-ID: USECASEUI-194
    Signed-off-by: guochuyicmri <guochuyi@chinamobile.com>
    
1 file changed