remap: don't try to remap other files in /proc

We can't remap these files correctly anyway, so we should just return success
if we find one of these files to remap.

v2: don't try to remap accessible files in /proc

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>