aufs5 GIT release (v6.0)

[J. R. Okajima]

o news
- linux-v6.0 is released and aufs5.x-rcN branch supports it.
- note that core file produced by linux-v6.0 is broken. the bug is fixed
  just after linux-v6.0 is released.
- git repositories for aufs6 will appear in a week or two.

J. R. Okajima