qtmod_test: fixed handling of no_default_install subdirs
qtmod_test: fixed handling of no_default_install subdirs

When testing the installation of Qt, we were doing (effectively) a
top-level `make install', relying on the fact that install targets
depend on compile targets, to compile and install everything in the
right order.

However, this meant that any subdir whose CONFIG included
no_default_install was omitted from this step, and potentially wouldn't
be tested.

Notably, the autotests in each Qt module are set up with
no_default_install, which means the tests were not built until `make
check' was run.  Since we have to run `make check' with -j1 to run the
tests one at a time, this meant the tests were being compiled more
slowly than necessary.

Change-Id: I8629c15aa9d65297259608e0213a43a57d0ddf3f
Sanity-Review: Qt Sanity Bot <5581206bb7e0307f0d99eb71898ae6b694149ca5@ovi.com>
Reviewed-by: Jyri Tahtela <f4a6700497ee4baf1b609e02c6d9f260ad39b761@nokia.com>

tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa