KVM test: deal with incompatible env files gracefully (using version numbers)

Keep a version number in kvm.py (env_version) and record it in new env objects.
When loading an env file, compare its version against env_version.  If it's too
old, don't use it.
When changes are made to the KVM test that break compatibility with existing
env files, env_version should be increased.

This will prevent exceptions being raised due to newly added VM attributes that
are missing from old env files.

Signed-off-by: Michael Goldish <mgoldish@redhat.com>



git-svn-id: http://test.kernel.org/svn/autotest/trunk@4713 592f7852-d20e-0410-864c-8624ca9c26a4
2 files changed