Better handling of errors from ovftool

[glennmatthews]

If cot deploy fails due to an ovftool failure, the error message from ovftool is not always very useful. The end user doesn't necessarily realize that this is ovftool and not COT being unhelpful, so it makes COT look bad. Would be nice to gather additional information in case of an ovftool failure.

Example: A user encountered the following error:

$ cot deploy -s '172.25.1.4/iSVC-DC/host/172.25.1.101' -P -u [email protected] -p XErg_lab123 -n "CSR205" -c 1CPU-4GB  -N "GigabitEthernet1=Management_172_25"  -N "GigabitEthernet2=Network1" -N "GigabitEthernet3=Network1" -N "GigabitEthernet4=Network1" -N "GigabitEthernet5=Network1" -N "GigabitEthernet6=Network1"  esxi "csr1000v-universalk9.03.15.00.S.155-2.S-std.ova" -ds=datastore1
Deploying VM...
Opening OVA source: csr1000v-universalk9.03.15.00.S.155-2.S-std.ova
Opening VI target: vi://administrator%[email protected]:443/iSVC-DC/host/172.25.1.101
Error:
 - The operation is not allowed in the current state of the host.
Completed with errors
Helper program 'ovftool' exited with error 1

The actual issue was that the datastore for this host needed to be "datastore1 (3)"not "datastore1" but this is not at all obvious from the ovftool error.

[glennmatthews]

Of course if we fix #6 then this issue becomes moot :)