Fix qbs submodule installation.

We want the qbs library and resources to be placed in
the canonical places when installing Qt Creator. This
also makes it necessary to change the location of the
respective files in the build directory.

Change-Id: I8e78ec5aa0e8b728ccca96d45a647c1488961ea0
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>