Qt 5.6 builds with relative RPATH by default on Linux.
Since this additionally leads to very short RPATHs,
we cannot change the relative structure within the
Qt installation (e.g. plugins in bin/, libs somewhere
in lib/qtcreator/).
Instead we now deploy qt into a self-contained lib/Qt/
folder, keeping the original structure, on Linux.

Change-Id: I36136590379c3e7b02ba7de3345369e2384dcc95
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>