Bug Description: In ndn_cache_lookup, to determine the given dn
is already normalized or not, the length is compared with the
normalized dn length. If they match, it considers the given dn
is already normalized. But there are cases even if the lengths
are equal, the given dn may not be normalized yet.
(e.g., 'cn="o=ABC",o=XYZ' vs. 'cn=o\3DABC,o=XYZ')
Fix Description: This patch adds another check: if the dn and
normalized dn length match, call memcmp to compare the 2 dn's.
When memcmp returns 0, ndn_cache_lookup returns the passed dn.