Fix javadoc warning for non-fully-qualified class link

Referring to this one user of the class seemed too specific, so
reworded to be more generic, which does not require a link at all.

Change-Id: I53e03b4c2f650f8aa870c07a5bedebee19f1a5d1

gerrit-httpd/src/main/java/com/google/gerrit/httpd/GetUserFilter.java

@@ -34,8 +34,7 @@ import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 
 /**
- * Stores user as a request attribute, so the servlet container access log like
- * {@link HttpLog} can include the the user for the request outside of the
+ * Stores user as a request attribute, so servlets can access it outside of the
  * request scope.
  */
 @Singleton