CodeCoverage: Fixes regression.

CodeCoverage: Fixes regression.

Fixes segmentation fault introduced by qtbase change:
36f5cc848de2525

Coverage data are now saved in QTestLog::stopLogging. Also the current
application name needs to be set for a quick test as well.

Remove also code coverage call to installCodeCoverage from quicktest
due to refactor of the code coverage setup in qtestlib. This should be less
error-prone. See qtbase change:
949b7452e0d2402

Change-Id: I13566cc43dfb3af264d3b2be2e5f2617128f4801
Reviewed-by: Caroline Chao <caroline.chao@nokia.com>