GERONIMO-6565 don't append separator if not needed, thanks Matthew Broadhead for the patch

git-svn-id: https://svn.apache.org/repos/asf/geronimo/javamail/trunk@1791820 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/store/imap/IMAPFolder.java b/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/store/imap/IMAPFolder.java
index ab65156..10a8053 100644
--- a/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/store/imap/IMAPFolder.java
+++ b/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/store/imap/IMAPFolder.java
@@ -1580,7 +1580,10 @@
     protected synchronized Folder[] filterFolders(String pattern, boolean subscribed) throws MessagingException {
         IMAPConnection connection = getConnection();
         // this is used to filter out our own folder from the search
-        String root = fullname + getSeparator();
+        String root = fullname;
+        if (!root.isEmpty()) {
+            root = root + getSeparator();
+        }
 
         List responses = null;
         try {