Qt5 CI: deploy solution for GL2 testing on VMs without hardware acceleration

Our test VMs do not simulate GL2-capable hardware and our base platform Ubuntu 10.04 doesn't appear to ship with a good enough software GL implementation by default. This causes latest QtDeclarative from Qt5 to be currently untestable.

This may be fixable by deploying a newer mesa. The following process is alleged to work:

1. apt-get install llvm
2. Install Mesa with llvm:

       wget ftp://ftp.freedesktop.org/pub/mesa/7.10.2/MesaLib-7.10.2.tar.bz2
       (unpack)
       ./configure --enable-gles2 --enable-gallium-llvm --disable-glut --with-driver=xlib --with-egl-platforms=x11
       make
       make install

3. build Qt
4. set LD_LIBRARY_PATH to point to gallium libGL
5. run tests and all is well

Rather than following the above verbatim, we would probably seek to deploy some new mesa .debs via puppet.