Hopefully fix the crash when updating from 0.9.7 or earlier

For backwards-compatibility reasons, we can only add struct members to the
end. That way, existing callers still can use newer libraries, as the
structs are always allocated by the library (and therefore guaranteed to
have the correct size) and still rely on the same position of the parts
the callers know about.

Reported by Luca Falavigna.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

rfb/rfbclient.h

@@ -192,9 +192,6 @@ typedef struct _rfbClient {
 	rfbPixelFormat format;
 	rfbServerInitMsg si;
 
-	/* listen.c */
-        int listenSock;
-
 	/* sockets.c */
 #define RFB_BUF_SIZE 8192
 	char buf[RFB_BUF_SIZE];
@@ -273,7 +270,6 @@ typedef struct _rfbClient {
 	SoftCursorLockAreaProc SoftCursorLockArea;
 	SoftCursorUnlockScreenProc SoftCursorUnlockScreen;
 	GotFrameBufferUpdateProc GotFrameBufferUpdate;
-	FinishedFrameBufferUpdateProc FinishedFrameBufferUpdate;
 	/** the pointer returned by GetPassword will be freed after use! */
 	GetPasswordProc GetPassword;
 	MallocFrameBufferProc MallocFrameBuffer;
@@ -325,6 +321,11 @@ typedef struct _rfbClient {
 
         /** hook to handle xvp server messages */
 	HandleXvpMsgProc           HandleXvpMsg;
+
+	/* listen.c */
+        int listenSock;
+
+	FinishedFrameBufferUpdateProc FinishedFrameBufferUpdate;
 } rfbClient;
 
 /* cursor.c */