fix mode settings on /tmp mount

Change the mode from 0777 to 1777 so it has the sticky dir bit set.
This is what all temp dirs should have so the kernel enforces sane
behavior across diff uids.

Bug: None
Test: `minijail0 -vt -- /bin/sh -c 'mount; ls -ld /tmp'` shows /tmp using 1777
Change-Id: I96d77a9bda76323993fed8d127f5df865f6477a2
2 files changed