alignment sosa to ssn

SSN subgroup,
Just for the record (I feel somewhat ridiculous saying this):

We, the ssn focus group have been assured on more than one occasion that we are to take no notice of 'https://github.com/w3c/sdw/blob/gh-pages/ssn/rdf/ssn-sosa.ttl"  (nor any other of the files in  https://github.com/w3c/sdw/tree/gh-pages/ssn/rdf , with the exception of sosa.ttl) and this is only a way of documenting someone's opinion and has no status more than that.

Therefore , we are safe to assume the fact that it is being updated very recently  does not change that status. https://github.com/w3c/sdw/commit/c52f0174ab8feca0e325cf22e487c85dfb3a096a

(Sorry folks,  just  preparing for the expected  "...but we all decided that.  Because it has been there  in public all this time , and so it's all done ...."  type claim).

ISSUE-139
-Kerry