Bug #220375 --> fix imap subscribe UI to always start up collapsed, so we don't run into a situation where we don't know that folders have children,

patch by bienvenu

mail/base/content/subscribe.xul

@@ -94,7 +94,8 @@
               seltype="multiple"
               datasources="rdf:null"
               flags="dont-build-content"
-              disableKeyNavigation="true"
+              disableKeyNavigation="true"
+              statedatasource="rdf:null"
               onkeypress="onSubscribeTreeKeyPress(event);"
               onclick="SubscribeOnClick(event);"> 
           <template>