Impossible to create a click chroot with encrypted home folder (ecryptfs)

[Nicolas DERIVE]

When creating a click chroot, for example with:

sudo click chroot -a armhf -f ubuntu-sdk-15.04 create

I got this error after configuring packages:

E: 10mount: umount: /var/lib/schroot/mount/click-ubuntu-sdk-15.04-armhf-3c1862b7-c6db-499e-9c1b-245951bf8305/home/nicolas: target is busy
E: 10mount: (In some cases useful info about processes that
E: 10mount: use the device is found by lsof(8) or fuser(1).)
E: click-ubuntu-sdk-15.04-armhf-3c1862b7-c6db-499e-9c1b-245951bf8305: Chroot setup failed: stage=setup-stop
Command returned 1: schroot -u root -c source:click-ubuntu-sdk-15.04-armhf -- /finish.sh
umount: /var/lib/schroot/mount/click-ubuntu-sdk-15.04-armhf-3c1862b7-c6db-499e-9c1b-245951bf8305/home/nicolas: target is busy
        (In some cases useful info about processes that
         use the device is found by lsof(8) or fuser(1).)
umount: /var/lib/schroot/mount/click-ubuntu-sdk-15.04-armhf-3c1862b7-c6db-499e-9c1b-245951bf8305/home: target is busy
        (In some cases useful info about processes that
         use the device is found by lsof(8) or fuser(1).)
umount: /var/lib/schroot/mount/click-ubuntu-sdk-15.04-armhf-3c1862b7-c6db-499e-9c1b-245951bf8305: target is busy
        (In some cases useful info about processes that
         use the device is found by lsof(8) or fuser(1).)
Traceback (most recent call last):
  File "/usr/bin/click", line 86, in <module>
    sys.exit(main())
  File "/usr/bin/click", line 82, in main
    return mod.run(args)
  File "/usr/lib/python3/dist-packages/click/commands/chroot.py", line 266, in run
    return args.func(parser, args)
  File "/usr/lib/python3/dist-packages/click/commands/chroot.py", line 68, in create
    return chroot.create(args.keep_broken_chroot)
  File "/usr/lib/python3/dist-packages/click/chroot.py", line 565, in create
    self.destroy()
  File "/usr/lib/python3/dist-packages/click/chroot.py", line 663, in destroy
    shutil.rmtree(chroot_dir)
  File "/usr/lib/python3.4/shutil.py", line 468, in rmtree
    _rmtree_safe_fd(fd, path, onerror)
  File "/usr/lib/python3.4/shutil.py", line 410, in _rmtree_safe_fd
    onerror(os.rmdir, fullname, sys.exc_info())
  File "/usr/lib/python3.4/shutil.py", line 408, in _rmtree_safe_fd
    os.rmdir(name, dir_fd=topfd)
OSError: [Errno 16] Device or resource busy: 'home'

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: click 0.4.39.1+15.10.20150702-0ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3
Uname: Linux 4.2.0-16-generic x86_64
ApportVersion: 2.19.1-0ubuntu2
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Oct 14 20:13:55 2015
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-03-30 (198 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Alpha amd64 (20150317.1)
SourcePackage: click
UpgradeStatus: Upgraded to wily on 2015-09-18 (26 days ago)

[Sebastien Bacher (seb128)]

that seems similar to bug #1427264