Merge remote-tracking branch 'hartwork:one-more-umount-fix'

PR 82 on github

Conflicts:
	grml-debootstrap

diff --cc grml-debootstrap
index 89c56f4,cf9d00b..07b769d
--- 1/grml-debootstrap
--- 2/grml-debootstrap
+++ b/grml-debootstrap
@@@ -1132,8 -1130,7 +1132,8 @@@ finalize_vm() 
  
    umount "${MNTPOINT}"/proc
    umount "${MNTPOINT}"/sys
-   umount "${MNTPOINT}"/dev
 +  umount "${MNTPOINT}"/dev/pts
+   try_umount 3 "${MNTPOINT}"/dev
    umount "${MNTPOINT}"
    kpartx -d "${ORIG_TARGET}" >/dev/null
  }