perf ordered_events: Clear the progress bar at the end of a flush

perf ordered_events: Clear the progress bar at the end of a flush

We were depending on the next screen operation after a flush() being
one that would redraw the whole screen so that the progress bar would
be overwritten, when that didn't happen a screen artifact of, say, a
error dialog window would be overlaid on top of the progress bar, fix
it by calling ui_browser__finish(), that now has a TUI implementation.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-el0fyw6duemnx62lydjzhs8c@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>