Correct JSON in json PMDA README
Correct JSON in json PMDA README

There was a stray comma (',') in the README example JSON.  If someone
tried to use that directly by copying and pasting it into a file, the
JSON parser would flag it as invalid.

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp