Some minor enhancements to install scripts

 - Fix some typos/nits
 - Make the script runnable with sudo
 - Check for sudo/root before starting

Change-Id: I9128d4d4ae981c757028d583f08b5be1b1b12c24
Expose time zone in user.common.yaml

The puppet-coi module has a parameter for setting the time zone
as well as a list of NTP servers, but currently user.common.yaml
only has data for the servers.  This commit adds a variable for
the time zone so that users know they can modify it according
to what time zone they're in.  It defaults to UTC as that's
also the default for lower-level classes.

Requires a puppet-coi containing 0ccb122 to be useful.

Change-Id: I6914bb86d916e262de532e42227b978f4a8eca1c
Merge "Some minor enhancements to install scripts"