perf annotate: Handle lower case key code in annotate_browser__run()

perf annotate: Handle lower case key code in annotate_browser__run()

Accepting upper case character only is unconvenient since it requires
SHIFT key too. Why not change to it accept a simple key stroke?

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/1329986784-4916-3-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>