Do not delete input variable, only remove callbacks (and all of them).

Otherwise, every one would have to check the return value of var_Get ...

src/input/input.c

@@ -1271,7 +1271,7 @@ static void End( input_thread_t * p_input )
     input_ChangeState( p_input, END_S );
 
     /* Clean control variables */
-    input_ControlVarClean( p_input );
+    input_ControlVarStop( p_input );
 
     /* Clean up master */
     InputSourceClean( &p_input->p->input );

src/input/input_internal.h

@@ -314,7 +314,7 @@ sout_instance_t * input_DetachSout( input_thread_t *p_input );
 
 /* var.c */
 void input_ControlVarInit ( input_thread_t * );
-void input_ControlVarClean( input_thread_t * );
+void input_ControlVarStop( input_thread_t * );
 void input_ControlVarNavigation( input_thread_t * );
 void input_ControlVarTitle( input_thread_t *, int i_title );