[1539] some wording updates to log description for AUTH_MESSAGE_FORWARD_ERROR.

- use recipient instead of forwarded as it seemed more intuitive
- descirbe how the request is responded
- use 'component' instead of 'program' where it's more appropriate
- use 'process' instead of 'program' where it's more appropriate

src/bin/auth/auth_messages.mes

@@ -258,15 +258,16 @@ will return an error code of NOTIMPL to the sender.
 % AUTH_MESSAGE_FORWARD_ERROR failed to forward %1 request from %2: %3
 The authoritative server tried to forward some type DNS request
 message to a separate process (e.g., forwarding dynamic update
-requests to b10-ddns) to handle it, but it failed.  It could be
-configuration mismatch between b10-auth and the forwarded program, or
-it may because the requests are coming too fast and the forwarded
-program cannot keep up with the rate, or some system level failure.
-In either case this means the BIND 10 system is not working as
-expected, so the administrator should look into the cause and address
-the issue.  The log message includes the client's address (and port),
-and the error message sent from the lower layer that detects the
-failure.
+requests to b10-ddns) to handle it, but it failed.  The authoritative
+server returns SERVFAIL to the client on behalf of the separate
+process.  The error could be configuration mismatch between b10-auth
+and the recipient component, or it may be because the requests are
+coming too fast and the receipient process cannot keep up with the
+rate, or some system level failure.  In either case this means the
+BIND 10 system is not working as expected, so the administrator should
+look into the cause and address the issue.  The log message includes
+the client's address (and port), and the error message sent from the
+lower layer that detects the failure.
 
 % AUTH_XFRIN_CHANNEL_CREATED XFRIN session channel created
 This is a debug message indicating that the authoritative server has