[CX] Cancel button uses Query service cancel syntax for Analytics service

Clicking the cancel button sends 

2017-08-08T20:44:21.853-07:00 INFO CBAS.server.QueryServiceServlet [HttpExecutor(port:8095)-7] {"host":"172.23.109.250:8091","path":"/query/service","statement":"delete from system:active_requests where clientContextID = \\\"aa7776a8-d869-490a-80fc-380644e653d2\\\";","pretty":false,"mode":null,"clientContextID":null}