Use QtGlesStream instead of Mesa

Build QtGlesStream dummy client and use the EGL headers from there,
instead of Mesa. The actual QtGlesStream module still needs to build
elsewhere.

Task-number: QTEE-557
Change-Id: I2d50522b920fb49eaf5086b105fc2e6e37eef686
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>