Fix Makefile rules for QCHelper.hs
Fix Makefile rules for QCHelper.hs

Include QCHelper.hs in the distributed files, and also exclude it and
the THH.hs file from coverage reports.

Signed-off-by: Iustin Pop <acf83a5274f31a43af6b914614365999469c1a31@google.com>
Reviewed-by: Andrea Spadaccini <92d490849ac1b40cd8e8878e4d94603bebdb089f@google.com>

ganeti-github-testing/ganeti-test-1,onponomarev/ganeti,grnet/snf-ganeti,dimara/ganeti,mbakke/ganeti,bitemyapp/ganeti,leshchevds/ganeti,apyrgio/snf-ganeti,andir/ganeti,mbakke/ganeti,grnet/snf-ganeti,ganeti-github-testing/ganeti-test-1,ganeti/ganeti,yiannist/ganeti,ganeti/ganeti,andir/ganeti,yiannist/ganeti,andir/ganeti,yiannist/ganeti,leshchevds/ganeti,onponomarev/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,bitemyapp/ganeti,apyrgio/ganeti,dimara/ganeti,leshchevds/ganeti,apyrgio/ganeti,ganeti/ganeti