[t:3178] Centralize panic handling, do not run library destructor if env is panicked.  Note, logger panic does not disable library destructor, perhaps it should.  Note, failed assert causes env panic, disabling library destructor.

git-svn-id: file:///svn/toku/tokudb@27354 c7de825b-a66e-492c-adef-691d508d4ae1