Fix "mac is not defined" bug in clone script

Since updating the 'rhev-template-clone.py' script to always convert the
mac address to lower case, the script was broken if a mac address was
provided by the user. This change is an attempt to fix that.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Allow a second for the VM to settle after boot

I've run into an issue where the 'arp4ip' function fails to match a VM's
mac address with the 'arp -n' output when run via the
'rhev-template-clone.py' script. To try an alleviate this issue, the
script now sleeps for a second before trying to determine the IP
address. This has proven to fix the issue in the very limited testing
done so far.

Signed-off-by: Prakash Surya <surya1@llnl.gov>