fix for #17961 - add defaults for some POP settings

r=sspitzer

mailnews/mailnews.js

@@ -355,3 +355,5 @@ pref("mail.collect_email_address", true);
 pref("mail.default_sendlater_uri","mailbox://nobody@Local Mail/Unsent Messages");
 
 pref("mail.server.default.port", -1);
+pref("mail.server.default.leave_on_server", false);
+pref("mail.server.default.download_on_biff", true);

modules/libpref/src/init/mailnews.js

@@ -355,3 +355,5 @@ pref("mail.collect_email_address", true);
 pref("mail.default_sendlater_uri","mailbox://nobody@Local Mail/Unsent Messages");
 
 pref("mail.server.default.port", -1);
+pref("mail.server.default.leave_on_server", false);
+pref("mail.server.default.download_on_biff", true);