remove screen workaround

Turns out elephant's oldusenet shellbox docker instance somehow had a
non-setguid screen binary. Dunno how; reinstall fixed it.

src/Propellor/Property/SiteSpecific/JoeySites.hs

@@ -88,9 +88,6 @@ oldUseNetInstalled pkg = check (not <$> Apt.isInstalled pkg) $
 			, "dpkg -i ../" ++ pkg ++ "_*.deb || true"
 			, "apt-get -fy install" -- dependencies
 			, "rm -rf /root/tmp/oldusenet"
-			-- screen fails unless the directory has this mode.
-			-- not sure what's going on.
-			, "chmod 775 /var/run/screen"
 			] `describe` "olduse.net built"
 		]