trace-view: Do not destroy spin button on freeing store
trace-view: Do not destroy spin button on freeing store

When the TraceViewStore was finalized, it would destroy the associated
spin button attached to it. But a new store may be using it.
Just unref the spin.

Signed-off-by: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>

bigzz/trace-cmd,bigzz/trace-cmd