Don't emit a warning message on missing PR_SET_NO_NEW_PRIVS

If the kernel doesn't support PR_SET_NO_NEW_PRIVS, then
don't print a warning message. The warning message only serves
to confuse other people.

This change assumes that, if EINVAL is returned, the kernel is an
old kernel. Newer kernels have no option to disable PR_SET_NO_NEW_PRIVS,
so IMHO, this is a fair assumption.

Change-Id: I77b4769e1d93a9b2412ba5365227283761940fdc
1 file changed