commit 4e1351a0610c6b2191a666a056609292a5f1ee81
author Alex Van Damme <atv@google.com> Wed May 30 13:21:45 2018 -0700
committer Alex Van Damme <atv@google.com> Wed May 30 13:23:33 2018 -0700
tree 44a0381f15f8358cf89f04a46a94496605f4c2b9
parent 23acda2994801149f1b3a4a234c5ffc96028a8a3

Remove recursive unmount

Sigh, Kokoro's umount doesn't support recursive:
sudo umount -R
/tmpfs/src/git/out/target/product/imx8m_phanbell/obj/ROOTFS/rootfs
umount: invalid option -- 'R'
Usage: umount -h | -V
       umount -a [-d] [-f] [-r] [-n] [-v] [-t vfstypes] [-O opts]
       umount [-d] [-f] [-r] [-n] [-v] special | node...
make: *** [/tmpfs/src/git/out/target/product/imx8m_phanbell/obj/ROOTFS/rootfs.raw.img] Error 1

- Remove the -R option from umount commands. Also add an unmount for
/dev/pts, as it was being unmounted by way of the recursive unmount.

Change-Id: I4e2bc0eb463db1a31d9bf9ffcd525c0f24958406