Fix parsing of emulated enabled DN

If a non-default emulated enabled DN is specified in configuration,
the DN structure returned from python-ldap is incorrectly converted
to a string.  This leads to an index error when we attempt to extract
the RDN attribute and value.

This patch removes the incorrect string conversion and instead does
the proper conversion on the RDN strings that we extract.

Change-Id: I8f0c4594cfa9a41e1875870c3eb63fae32c8c041
Resolves-bug: #1375772
(cherry picked from commit 5380ddaadb0ce34b866b097cb6ac1396d2b30100)
Merge "Fix parsing of emulated enabled DN" into proposed/juno