BaseServlet: Add Javadoc for IOException to prevent Eclipse warnings

The IOException is not thrown from the methods as implemented in the
base class, but from the overridden implementations in the derived
classes.

Add Javadoc @throws tags to prevent Eclipse from complaining that the
exceptions are not thrown.

Change-Id: I55a225a80b819b2156c52fffe0e2f87482a5abb5

java/com/google/gitiles/BaseServlet.java

diff --git a/java/com/google/gitiles/BaseServlet.java b/java/com/google/gitiles/BaseServlet.java
index 02a3f1a..6a2e5eb 100644
--- a/java/com/google/gitiles/BaseServlet.java
+++ b/java/com/google/gitiles/BaseServlet.java
@@ -145,6 +145,7 @@
    *
    * @param req in-progress request.
    * @param res in-progress response.
+   * @throws IOException if there was an error rendering the result.
    */
   protected void doGetHtml(HttpServletRequest req, HttpServletResponse res) throws IOException {
     throw new GitilesRequestFailureException(FailureReason.UNSUPPORTED_RESPONSE_FORMAT);
@@ -155,6 +156,7 @@
    *
    * @param req in-progress request.
    * @param res in-progress response.
+   * @throws IOException if there was an error rendering the result.
    */
   protected void doGetText(HttpServletRequest req, HttpServletResponse res) throws IOException {
     throw new GitilesRequestFailureException(FailureReason.UNSUPPORTED_RESPONSE_FORMAT);
@@ -165,6 +167,7 @@
    *
    * @param req in-progress request.
    * @param res in-progress response.
+   * @throws IOException if there was an error rendering the result.
    */
   protected void doGetJson(HttpServletRequest req, HttpServletResponse res) throws IOException {
     throw new GitilesRequestFailureException(FailureReason.UNSUPPORTED_RESPONSE_FORMAT);