Do not wrap particles until rebuilding the tree

This was causing the tree to never be rebuilt because the particles were
wrapped back into the primary image before the displacement check was
performed. And since the diaplacement check used the minimum
plane-to-plane distance, the particle could never really move far enough
to trigger a rebuild. This may have been leading to rare overlaps.

hoomd/hpmc/UpdaterVirtualMoveMonteCarlo.h

@@ -1128,7 +1128,6 @@ template<class Shape> void UpdaterVMMC<Shape>::update(uint64_t timestep)
                             vec3<Scalar> new_pos = m_positions_after_move[idx];
                             h_postype.data[idx]
                                 = make_scalar4(new_pos.x, new_pos.y, new_pos.z, postype_idx.w);
-                            box.wrap(h_postype.data[idx], h_image.data[idx]);
                             vec3<Scalar> displacement
                                 = vec3<Scalar>(h_postype.data[idx])
                                   - vec3<Scalar>(h_pos_last_tree_build.data[idx]);
@@ -1149,13 +1148,16 @@ template<class Shape> void UpdaterVMMC<Shape>::update(uint64_t timestep)
                         // update pos_last_tree_build
                         for (unsigned int idx = 0; idx < m_pdata->getN(); idx++)
                             {
+                            box.wrap(h_postype.data[idx], h_image.data[idx]);
                             h_pos_last_tree_build.data[idx] = h_postype.data[idx];
                             }
+                        m_count_total.num_aabbtree_builds++;
                         }
                     else
                         {
                         for (unsigned int idx = 0; idx < m_pdata->getN(); idx++)
                             {
+                            // TODO: only loop over the m_cluster_data elements
                             if (!(m_cluster_data.m_linkers_added.find(idx)
                                   == m_cluster_data.m_linkers_added.end()))
                                 {