Don't open the control socket until after the server socket is bound

This makes it easier for the tests (and supervisor) to guarantee to be
able to connect to the server socket.

Also this patch moves freeing the mirror supervisor into the server
thread.

src/mode.c

@@ -187,7 +187,6 @@ char * help_help_text = help_help_text_arr;
 
 
 
-int do_serve(struct server* params);
 void do_read(struct mode_readwrite_params* params);
 void do_write(struct mode_readwrite_params* params);
 void do_remote_command(char* command, char* mode, int argc, char** argv);