Backport security fix r16747 from trunk

Backport security fix r16747 from trunk

1. Disable fleshing for PCRUD.  Otherwise fleshing would provide a
back door whereby a user could see stuff he has no permission to see.

2. For the id_list method: strip out the "flesh_fields" entry, not
the "flesh_columns" entry (which doesn't exist).  This actually makes
no difference, but if we're going to do something useless, we might
as well do it right.

git-svn-id: svn://svn.open-ils.org/ILS/branches/rel_1_6@16748 dcc99617-32d9-48b4-a31d-7c20da2025e4