Another optimization.

git-svn-id: http://svn.igniterealtime.org/svn/repos/messenger/trunk@3152 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/messenger/SessionManager.java

@@ -821,7 +821,7 @@ public class SessionManager extends BasicModule {
 
         ClientSession session = null;
         // Build a JID represention based on the given JID data
-        StringBuilder buf = new StringBuilder();
+        StringBuilder buf = new StringBuilder(40);
         if (username != null) {
             buf.append(username).append("@");
         }