Fix authentication failure warning log messages for FEDERATION_USER

Dariusz Bywalec

2016-01-04 5274e12c7cc19451355082418f78004c4d97e263

 src/main/java/com/gitblit/manager/AuthenticationManager.java

@@ -466,6 +466,12 @@
         return null;
      }

      if (username.equalsIgnoreCase(Constants.FEDERATION_USER)) {
         // can not authenticate internal FEDERATION_USER at this point
         // it must be routed to FederationManager
         return null;
      }
		
      String usernameDecoded = StringUtils.decodeUsername(username);
      String pw = new String(password);
      if (StringUtils.isEmpty(pw)) {