appliance: Set udev.event-timeout to override default too low udev setting.

Unfortunately udev removed the udevtimeout setting on the kernel
command line.  This means the default timeout was being set back to 30
seconds, which is way too low for remote disks.

However it was re-added (2014-07-29) as udev.event-timeout.  Set both
to be sure.

Note this requires systemd >= 216.
v2v: Increase vCenter https timeout to 10 minutes.