Reduce quiesced snapshot warning messages when running on older hosts.

Reduce quiesced snapshot warning messages when running on older hosts.

vSphere 6.7 added a new interface on the host side that allows tools
to send a "generic" backup manifest during a quiesced snapshot on
Linux guests. VMTools 10.2.0 or later will try to send the manifest
file and if the host is unable to field it, then VMTools logs this
information and continues with the quiesced snapshot in the older
fashion.  This change reduces the logging that is done in this case.