Fix NPE when there are two repositories which only differ in case

Sascha Vogt

2014-06-18 396e9bb50d7eca0d96da2c5fc5177a22f78d30b7

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

@@ -24,6 +24,7 @@
    *
    * @param username
    * @return true if the specified username represents an internal account
     * @since 1.4.0
    */
   boolean isInternalAccount(String username);