update disk size before local disk migration

update disk size before local disk migration

Split out 'update_disksize' from the renamed 'update_disk_config' to
allow code reuse in QemuMigrate.

Remove dots after messages to keep style consistent for migration log.

After updating in sync_disks (phase1) of migration, write out updated
config. This means that even if migration fails or is aborted in later
stages, we keep the fixed config - this is not an issue, as it would
have been fixed on the next attempt anyway, and it can't hurt to have
the correct size instead of a wrong one either way.

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