kernelshark: Clean up event dialog code
kernelshark: Clean up event dialog code

Use gtk_dialog_run() and examine the results instead of having
to create a helper structure that is allocated and passed back to
signals.

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

bigzz/trace-cmd,bigzz/trace-cmd