perf script: Also allow forcing reading of non-root owned files by root

In 2059fc7a ("perf symbols: Allow forcing reading of non-root owned
files by root") 'perf report' was added the option of forcing reading of
non-root owned symbol file.

This add the same behavior for perf script.

Reported-by: Mark Drayton <mbd@fb.com>
Signed-off-by: Yannick Brosseau <scientist@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: kernel-team@fb.com
Link: http://lkml.kernel.org/r/20170113182527.18625-1-scientist@fb.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>