Bug 1562326 - Remove observers from radio biffMinutes/biffDays so that radio buttons show up again. r=me

Follow-up to bug 1543771 where observers were removed in feed-subscriptions.xul already.

mailnews/extensions/newsblog/content/am-newsblog.xul

@@ -74,13 +74,9 @@
                     orient="horizontal"
                     oncommand="setPrefs(this)">
           <radio id="biffMinutes" value="min" label="&biffMinutes.label;"
-                 accesskey="&biffMinutes.accesskey;">
-            <observes element="updateValue" attribute="disabled"/>
-          </radio>
+                 accesskey="&biffMinutes.accesskey;"/>
           <radio id="biffDays" value="d" label="&biffDays.label;"
-                 accesskey="&biffDays.accesskey;">
-            <observes element="updateValue" attribute="disabled"/>
-          </radio>
+                 accesskey="&biffDays.accesskey;"/>
         </radiogroup>
       </hbox>