Implemented counters:
 VIR_DOMAIN_MEMORY_STAT_SWAP_IN
 VIR_DOMAIN_MEMORY_STAT_SWAP_OUT
 VIR_DOMAIN_MEMORY_STAT_MINOR_FAULT
 VIR_DOMAIN_MEMORY_STAT_MAJOR_FAULT
 VIR_DOMAIN_MEMORY_STAT_AVAILABLE
 VIR_DOMAIN_MEMORY_STAT_ACTUAL_BALLOON
 VIR_DOMAIN_MEMORY_STAT_UNUSED

Comments.

1. Use vzDomObjFromDomainRef/virDomainObjEndAPI pair to get domain
object as we use prlsdkGetStatsParam. See previous statistics
comments.

2. Balloon statistics is not applicable to containers. Fault
statistics for containers not provided in PCS6 yet.
Signed-off-by: NNikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>