Minor cleanup in AbstractIoHandler.sessionClosed() (#200)

Make sure QF_SESSION attribute gets removed in any case. SingleThreadedEventHandlingStrategy.onMessage might throw an Exception.

Author: chrjohn

quickfixj-core/src/main/java/quickfix/mina/AbstractIoHandler.java

@@ -110,12 +110,12 @@ public void sessionClosed(IoSession ioSession) throws Exception {
             Session quickFixSession = findQFSession(ioSession);
             if (quickFixSession != null) {
                 eventHandlingStrategy.onMessage(quickFixSession, EventHandlingStrategy.END_OF_STREAM);
-                ioSession.removeAttribute(SessionConnector.QF_SESSION);
             }
-            ioSession.closeNow();
         } catch (Exception e) {
-            ioSession.closeNow();
             throw e;
+        } finally {
+            ioSession.removeAttribute(SessionConnector.QF_SESSION);
+            ioSession.closeNow();
         }
     }