Multiple FreeBSD fixes

 - Fixup ovf-env.xml file broken by customdata
 - Fix new DistInfo() function for FreeBSD
 - Squelch a few (ignorable) errors in the log
 - Force ascii encoding for FreeBSD ovf-env.xml file
 - Strip non-XML data from ovf-env.xml file
 - Bail out properly when provisioning as DISK