339084 Fixed NPE with servlet 3.0 async listener

git-svn-id: svn+ssh://dev.eclipse.org/svnroot/rt/org.eclipse.jetty/jetty/trunk@2962 7e9141cc-0065-0410-87d8-b60c137991c4

VERSION.txt

@@ -4,6 +4,7 @@ jetty-7.4.0-SNAPSHOT
  + 338627 HashSessionManager.getIdleSavePeriod returns milliseconds instead of seconds
  + 338807 Ignore content length in 1xx, 204, 304 responses
  + 338819 Externally control Deployment Manager application lifecycle
+ + 339084 Fixed NPE with servlet 3.0 async listener
  + 339150 Validate client certificate when it is used for authentication
  + 339187 In the OSGi manifest of the jetty-all-server aggregate, mark javax.annotation as optional
  + 339543 Add configuration options for Certificate Revocation checking

jetty-continuation/src/main/java/org/eclipse/jetty/continuation/Servlet3Continuation.java

@@ -91,7 +91,7 @@ public class Servlet3Continuation implements Continuation
             }
         };
         
-        if (_context==null)
+        if (_context!=null)
             _context.addListener(wrapped);
         else
             _listeners.add(wrapped);