version_guard: early out when major/minor version is high enough

version_guard: early out when major/minor version is high enough

E.g.: If a feature requires 4.1+pveN and we're using machine version 4.2
we don't need to increase the pve version to N (4.2+pve0 is enough).

We check this by doing a min_version call against a non-existant higher
pve-version for the major/minor tuple we want to test for, which can
only work if the major/minor alone is high enough.

Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>