Bail out when VM is not ready after some time

Previously this situation was ignored resulting
in potential failures later on
Increase wait_for_ready_vm timeout to 20 seconds
Refresh VM details while waiting for VM to become ready
Add support for automatically resizing volumes
Bump dependency requirements
Merge pull request #2 from epienbroek/ready_status_logic

Various improvements in "make sure VM is ready to start" logic
Merge pull request #3 from epienbroek/volume_extend

Add support for automatically resizing volumes
Use the oVirt REST API to find out the guest IP address

This replaces the old nmap broadcast/arp hack which was
previously used to find out the guest IP address and also
allows the vagrant-ovirt plugin to be used from different
network subnets.

Requires https://github.com/fog/fog/pull/3162 and a box
image which contains the package 'ovirt-guest-agent'