Bug 1014820 - [Calendar] remove the waitForKeyboardHide from marionette tests r=gaye

executed all calendar tests more than 20+ on Travis and seems pretty stable. (https://travis-ci.org/millermedeiros/gaia/builds/26802654)

we have more than 30 calls to `createEvent` on the integration tests (some of them are subsequent calls), which means that if it didn't fail during 20 runs it probably should not fail if executed more times.