perf probe: Fix --line option behavior

The commit 5a62257a

 ("perf probe: Replace line_list with
intlist") replaced line_list to intlist but it has a problem that if a
same line was added again, it'd return -EEXIST rather than 1.

Since line_range_walk_cb() only checks the result being negative, it
resulted in failure or segfault sometimes.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/1396327677-3657-1-git-send-email-namhyung@kernel.org
Signed-off-by: Jiri Olsa <jolsa@redhat.com>