Merge branch 'stable-2.8' into master

Merge branch 'stable-2.8' into master

* stable-2.8:
  gnt-cluster info (py): add enabled disk templates
  Version bump to 2.8.0~beta1
  Change version numbers in documentation
  Fix issue with python coverage tests
  Merge branch 'stable-2.7' into stable-2.8
  Disable python test if required libraries are missing
  Better specify what packages to install
  Improve install guide
  Fix typo in the documentation index
  Fix typos in the documentation index
  Update security document wrt confd access to SSL cert
  Add tools for building deb packages to build_chroot
  Improve the final message of build_chroot
  Make build_chroot self-contained

Conflicts:
	configure.ac (trivial)
	lib/cmdlib/instance_storage.py (trivial)

The version numbers changed in 'Change version numbers in documentation'
and 'Version bump to 2.8.0~beta1' were adapted to 2.9.

Signed-off-by: Thomas Thrainer <thomasth@google.com>
Reviewed-by: Michele Tartara <mtartara@google.com>