clients/simple-egl: call eglSwapInterval after eglMakeCurrent

If weston-simple-egl is run with the "-b" flag, it will attempt to set the swap interval to 0 during create_surface. However, at that point, it will not have made its EGLContext current yet, causing the eglSwapInterval call to have no effect. To fix this, wait until the EGLContext has been made current in init_gl before updating the swap interval.

Signed-off-by: Erik Kurzinger ekurzinger@nvidia.com