perf hists: Collapse expanded callchains after filter is applied

perf hists: Collapse expanded callchains after filter is applied

When a filter is applied a hist entry checks whether its callchain was
folded and account it to the output stat.  But this is rather hacky
and only TUI-specific.  Simply fold the callchains for the entry looks
like a simpler and more generic solution IMHO.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1398327843-31845-6-git-send-email-namhyung@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>