clarify operating system requirement for service transition

tsa/policy/tpa-rfc-2-support.mdwn

@@ -218,10 +218,9 @@ In order for a service to be adopted by the sysadmin team:
     procedures,
  3. It needs to maintain a bug tracker and/or some means to contact
     upstream,
- 4. It needs to run on the lastest Debian stable,
- 5. When a new Debian release become stable it needs to support it
-    within 3 months.
- 6. At least one extra person from the Tor community should be willing
+ 4. It needs to work on a supported operating system (currently:
+    supported, non-EOL Debian GNU/Linux)
+ 5. At least one extra person from the Tor community should be willing
     to help to maintain the service in addition to one person from the
     sysadmin team.