The parameters count and instances in VertexDataManager::StoreStaticAttrib
are never used in the function body. So this patch will remove them.

BUG=none

Change-Id: Ic3fe21ae50e5016145bfd0c78542540c8ec76fd2
Reviewed-on: https://chromium-review.googlesource.com/445337
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Yunchao He <yunchao.he@intel.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>