drop reference to defunct multicorn2.org homepage

Author: luss

META.json

@@ -12,7 +12,6 @@
             "url":  "git://github.com/pgsql-io/multicorn2.git",
             "type": "git"
         },
-        "homepage": "http://multicorn2.org",
         "bugtracker": {
             "web": "https://github.com/pgsql-io/multicorn2",
             "mailto": "[email protected]"