[wrt][XWALK-1811][XWALK-1944]Fix XWALK-1811/1944 update the tcs

Impacted TCs num(approved): New 0, update 3, deleted 1
Unit test platform: [tizen]
Unit test result summary: Pass 3, Fail  0, Blocked 0
Merge pull request #334 from linshen/fix-xwalk-1691/1811

[wrt][XWALK-1811]Fix XWALK-1811 update the install command