perf annotate: Restore title when came back to original symbol

perf annotate: Restore title when came back to original symbol

On tui annotation, the title was set to name of the target symbol if
user selects the target. However it remained after returning to original
symbol from the target. Fix it.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1329986784-4916-4-git-send-email-namhyung.kim@lge.com
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>