meta: Fix the pbo usage in meta for GLES{1,2} contexts

meta: Fix the pbo usage in meta for GLES{1,2} contexts

OpenGL ES 1.0 doesn't support using GL_STREAM_DRAW and both
ES 1.0 and 2.0 don't support GL_STREAM_READ in glBufferData().
So, handle it correctly by calling the _mesa_meta_begin()
before create_texture_for_pbo().

V2: Remove the changes related to allocate_storage. (Ian)

Cc: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>