st/mesa: use _mesa_delete_buffer_object
st/mesa: use _mesa_delete_buffer_object

This is more future-proof than the current code.

Reviewed-by: Marek Olšák <8c7344a1abdb103e79ecfd488098373070c3c70e@amd.com>
Cc: "11.0 11.1" <59f39c0db42d4479a46b02d4d2bc11120e37bb44@lists.freedesktop.org>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler