Remove Support for VixDiskLib 5.1.0

VixDiskLib 5.1.0 has a known bug intermittently causing a
segfault during disk open operations when the vCenter Server
does not provide an SSL thumbprint for the target host.  The
code has been modified to allow unsupported versions to be
specified in the "bad_versions" array.

@roliveri @jrafanie @chessbyte please review.
 Normally RuboCop says that %w literals should be delimited by '(' and ')' although with only one entry it doesn't care either way.  However the intent is that this array may have additional members in which case I'd prefer to leave the line as is so that we don't have to change the delimiters again after adding another member.