Skip SSL verification when checking if the source file exists

[hlaf]

Enables the use of an ovf_source with a self-signed certificate and ensures consistency with the use of ovftool's '--noSSLVerify' option.

[josenk]

Not secure to set this. I think it would be better if you use real certs on your ovf_source urls. Let's Encrypt is a possible solution.

[hlaf]

I agree that this is not secure. I was misled by the use of the --noSSLVerify ovftool command-line option to build ovf_cmd, which seemed to suggest that SSL verification was to be skipped both for the destination and source connections. It seems that more recent versions of ovftool now have --noSourceSSLVerify and --noDestinationSSLVerify options to support use cases such as this one.