mesa: Fix geometry shader program queries.

The queries GEOMETRY_VERTICES_OUT, GEOMETRY_INPUT_TYPE, and
GEOMETRY_OUTPUT_TYPE (defined by GL 3.2) differ from the corresponding
queries in ARB_geometry_shader4 in the following ways:

- They use different enum values

- They can only be queried; they cannot be set.

- Attempting to query them yields INVALID_OPERATION if the program is
  not linked, or lacks a geometry shader.

This patch switches us over from the ARB_geometry_shader4 behaviour to
the GL 3.2 behaviour.

Fixes piglit test query-gs-prim-types.