mesa: Array uniform name length includes length of [0]

mesa: Array uniform name length includes length of [0]

This is required by OpenGL ES 3.0 and desktop OpenGL 4.2.  Previous
version were ambiguous.  This also matches the behavior of NVIDIA's
closed-source driver (version 304.64).

Fixed gles3conformance test uniform_buffer_object_getactiveuniformsiv
and uniform_buffer_object_structure_and_array_element_names (on my
in-progress branch that fixes a bunch of other stuff...YMMV).

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>