Merge pull request #1020 from pmcmaw/rm_d9

(maint) - Removing Debian 9

Author: willmeek

metadata.json

@@ -56,8 +56,7 @@
       "operatingsystem": "Debian",
       "operatingsystemrelease": [
         "7",
-        "8",
-        "9"
+        "8"
       ]
     },
     {