Use co-installable qca-qt5 version
Review Request #122155 - Created Jan. 19, 2015 and submitted
If both qt4 and qt5 versions of qca are present the build of the
frameworks branch tries to find Qt4 pulled in by qca and thus fails.
This is similiar to what has been done to konversation and muon
Note: I don't have commit access so I'd need someone to push this for me.
Successfully built with -DCMAKE_DISABLE_FIND_PACKAGE_Qca-qt5:BOOL=FALSE AND TRUE and okular linked to the right version of qca in the former case.