Move recognition of a templated attribute to ldap_attribute_to_rdatatype
    
    When substitution of a templated entry attribute fails, we need to fall
    back to a static definition of the attribute from the same entry. This
    means, however, that ldap_attribute_to_rdatatype() will attempt to parse
    an attribute value anyway and will be confused by the templating prefix,
    thus reporting in named's logs:
    
    unsupported operation: object class in resource record template DN
    'idnsname=$NAME,idnsname=$ZONE.,cn=dns,$BASEDN' changed:
    rndc reload might be necessary
    
    Move recognition of a template attribute name to
    ldap_attribute_to_rdatatype() so that a proper attribute class is
    correctly derived and ignore templated attribute in the fallback code
    if case that template expansion is failed.
    
    Resolves: rhbz#1705072