Wrap finalize spec cleanup in ensure blocks
Wrap finalize spec cleanup in ensure blocks

This means one spec failure won't cascade through the specs.  An after
block might seem to be the solution, but we'd need one per spec, which
means nested describes for no other reason than to clean up.

tillsc/dm-core,engineyard/dm-core,alloy/dm-core,datamapper/dm-core,ar-dm/ardm-core,tpitale/dm-core