Testsuite: Cleanup run_testsuite.cmake

This commit cleans up run_testsuite.cmake. It now

 - correctly determines and submits the branch name
 - writes a smaller revision.log without redundant information
 - does not set a subproject per branch anymore
Merge pull request #161 from tamiko/cleanup_run_testsuite_script

Testsuite: Cleanup run_testsuite.cmake

It now 
- correctly determines and submits the branch name
- writes a smaller revision.log without redundant information
- does not set a subproject per branch anymore