perf probe: Make -L display the absolute path of the dumped file

The actual file used by 'perf probe -L sched.c' is reported in the ouput
of the command.

But it's simply displayed as it has been given to the command (simply
sched.c) which is too ambiguous to be really usefull since several
sched.c files can be found into the same project and we also don't know
which search path has been used.

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
LKML-Reference: <1292854685-8230-2-git-send-email-fbuihuu@gmail.com>
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>