parse_build_log: handle incorrect ref / sha in sync.profile

In https://codereview.qt-project.org/23665 there was a change which put an incorrect branch name in sync.profile.

parse_build_log.pl didn't show anything about this: http://testresults.qt-project.org/ci/QtJsonDb_master_Integration/build_00777/linux-arm-gnueabi-g%2B%2B_Ubuntu_11.10_x86/log.txt.gz

It should be able to extract the failing part.