Fix a lock order reversal in uma_zdestroy.  The uma_mtx needs to be held across calls to zone_drain().
Fix a lock order reversal in uma_zdestroy.  The uma_mtx needs to be held across
calls to zone_drain().

Noticed by:	scottl

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase