stageuser-find: fix search with non-posix user
ipa stageuser-find fails to return a staged user if it does not
contain the posixaccount objectclass.
The code is replacing the search filter (objectclass=posixaccount)
with (|(objectclass=posixaccount)(objectclass=inetorgperson)) so it
should work in theory.
The issue is that on python2 the filter has been hexlified before
reaching the stageuser plugin, hence filter.replace does not recognize
the pattern (objectclass=posixaccount).
The fix consists in creating the filter with a call to
ldap.make_filter_from_attr()
that will hexlify too, if needed.
Fixes: https://pagure.io/freeipa/issue/7983
Reviewed-By: Rob Crittenden <rcritten@redhat.com>