(ITS#7906) segv when changing olcDbDirectory with ppolicy running

[ebackes@symas.com]

Full_Name: Emily Backes
Version: RE24
OS: Any
URL: 
Submission from: (NULL) (50.113.67.84)


While testing out the new mdb_copy compaction, I tried switching a live instance
to use a different db path via MOD to change olcDbDirectory.

This results in repeatable segv in ppolicy.c:ppolicy_connection_destroy, where
conn refers to the correction making the change that is likely in the process of
disconnecting, and pwcons is NULL.