Revision 1687980

*) mod_ldap: In some case, LDAP_NO_SUCH_ATTRIBUTE could be returned instead of
   an error during a compare operation. [Eric Covener]

+ accompanying trace.

Note: the if/else now matches (don't replace unknown compare errors with 
LDAP_NO_SUCH_ATTRIBUTE) the logic just above when pulling comparisons
out of the cache.