Explicitly declare charset when getting bytes from Soy index render

Change-Id: If99e77c7f8cda3af384808a362f52bb098172245
diff --git a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/raw/IndexServlet.java b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/raw/IndexServlet.java
index 4ac3da7..b55cf6c 100644
--- a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/raw/IndexServlet.java
+++ b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/raw/IndexServlet.java
@@ -47,7 +47,7 @@
             .newRenderer("com.google.gerrit.httpd.raw.Index")
             .setContentKind(SanitizedContent.ContentKind.HTML)
             .setData(getTemplateData(canonicalURL, cdnPath));
-    indexSource = renderer.render().getBytes();
+    indexSource = renderer.render().getBytes(UTF_8);
   }
 
   @Override