Add missing serialVersionUID to servlets

Change-Id: I430066f9f5903d9893882d8c8f3bbbdff8ce4b9e
Signed-off-by: Shawn O. Pearce <sop@google.com>

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

@@ -30,6 +30,7 @@ import javax.servlet.http.HttpServletResponse;
 
 @Singleton
 public class ChangeQueryServlet extends HttpServlet {
+  private static final long serialVersionUID = 1L;
   private final Provider<QueryProcessor> processor;
 
   @Inject

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

@@ -73,6 +73,7 @@ import javax.servlet.http.HttpServletResponse;
 /** Serves Git repositories over HTTP. */
 @Singleton
 public class ProjectServlet extends GitServlet {
+  private static final long serialVersionUID = 1L;
   private static final Logger log =
       LoggerFactory.getLogger(ProjectServlet.class);
 
@@ -131,6 +132,8 @@ public class ProjectServlet extends GitServlet {
     super.init(config);
 
     serveRegex("^/(.*?)/?$").with(new HttpServlet() {
+      private static final long serialVersionUID = 1L;
+
       @Override
       protected void doGet(HttpServletRequest req, HttpServletResponse rsp)
           throws IOException {

gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/openid/XrdsServlet.java

@@ -28,6 +28,7 @@ import javax.servlet.http.HttpServletResponse;
 
 @Singleton
 class XrdsServlet extends HttpServlet {
+  private static final long serialVersionUID = 1L;
   private static final String ENC = "UTF-8";
   static final String LOCATION = "OpenID.XRDS";
 

gerrit-httpd/src/main/java/com/google/gerrit/httpd/raw/ToolServlet.java

@@ -42,6 +42,7 @@ import javax.servlet.http.HttpServletResponse;
 /** Sends the client side tools we keep within our software. */
 @Singleton
 public class ToolServlet extends HttpServlet {
+  private static final long serialVersionUID = 1L;
   private final ToolsCatalog toc;
 
   @Inject