The rules for which version of the label specification are in effect at
any given point in time are as follows:
1/ If a DIMM has an existing / valid index block then the version
specified is used regardless if it is a previous version.
2/ By default when the kernel is initializing new index blocks the
latest specification version (v1.2 at time of writing) is used.
3/ An environment that wants to force create v1.1 label-sets must
arrange for userspace to disable all active regions / namespaces /
dimms and write a valid set of v1.1 index blocks to the dimms.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>