vzoversell: handle unlimited RAM CTs
Some containers might be configured as unlimited
(i.e. infinite physpages and privvmpages limit).
Also, a container might appear as unlimited while
it is being restored from dump (as beancounter limits
are initially set to unlimited and only set to proper
values at the end of the restoration process).
In case such unlimited containers are present,
overcommitment figures shown doesn't make sense,
> RAM available: 59.4G allocated: 16Z oversell: 29630589707078%
> Swap available: 177G allocated: 18.9G oversell: 10%
> RAM+Swap available: 237G allocated: 16Z oversell: 7411239850072%
The fix is to skip such containers, as we already do for
1 we do not just detect the unlimited container, but also
mark it with a flag ("U") and explain why.
2 RAM usage and peak usage of an unlimited container
is still being included into totals, it's just the limit
that is being ignored.
Signed-off-by: Kir Kolyshkin <email@example.com>