Remove declaration of onConnectedServerRegion from PsiphonTunnel.h

Note: this declaration should be added in another branch

MobileLibrary/iOS/PsiphonTunnel/PsiphonTunnel/PsiphonTunnel.h

@@ -319,12 +319,6 @@ WWAN or vice versa or VPN state changed
               connectedClients:(int)connectedClients
                        bytesUp:(long)bytesUp
                      bytesDown:(long)bytesDown;
-
-/*!
- Called when tunnel-core reports connected server region information
- @param region The server region received.
- */
-- (void)onConnectedServerRegion:(NSString * _Nonnull)region;
 @end
 
 /*!