HFX-1192: Clearwater SP1 hotfix: xapi fix for Time zone reset during VM migrations from pre-6.1 XS during RPU

merge from CA-128803: do not take timeoffset from last boot record for HFX-1192
This is specially for upgrades from pre-xenopsd XenServers.

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Merge pull request #1860 from zhengyul/HFX-1192

HFX-1192: Pick CA-128803:Time zone reset during VM migrations from pre-6.1 XS during RPU from creedence to clearwater-sp1-lcm