Load OpenGL ES 2.0 function procs

Load functions procs supported by OpenGL ES 2.0, though there is not a
compatible renderer yet. Change argument for GLimp_Init from coreContext
to fixedFunction.

code/renderergl2/tr_local.h

@@ -43,6 +43,7 @@ QGL_1_3_PROCS;
 QGL_1_5_PROCS;
 QGL_2_0_PROCS;
 QGL_3_0_PROCS;
+QGL_ARB_occlusion_query_PROCS;
 QGL_ARB_framebuffer_object_PROCS;
 QGL_ARB_vertex_array_object_PROCS;
 QGL_EXT_direct_state_access_PROCS;