Finalize 2.15.4 release notes

- Remove 'in development' caveat
- Add download and documentation links
- Update 'latest release'
- Add 2.15.4 in Elasticsearch compatibility table for ES 6.4

Change-Id: I3de3c5ce1d54302fe9d4344d3af4e0646f33fb0b
diff --git a/index.md b/index.md
index 12a9619..162ca8a 100644
--- a/index.md
+++ b/index.md
@@ -66,9 +66,9 @@
                 <div class="panel-body">
                     <h4>Download</h4>
                     <p>Our latest release is:<br>
-                    <b><a href="2.15.html">2.15.3</a></b>
+                    <b><a href="2.15.html">2.15.4</a></b>
                     </p>
-                    <a href="https://gerrit-releases.storage.googleapis.com/gerrit-2.15.3.war" class="btn btn-primary">Download</a>
+                    <a href="https://gerrit-releases.storage.googleapis.com/gerrit-2.15.4.war" class="btn btn-primary">Download</a>
                 </div>
             </div>
         </div>
@@ -111,16 +111,16 @@
 </tr>
 </table>
 
-Schedule [git gc](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15.3/config-gerrit.html#gc)
+Schedule [git gc](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15.4/config-gerrit.html#gc)
 over all managed repositories and
-[replicate](https://gerrit.googlesource.com/plugins/replication/+doc/v2.15.3/src/main/resources/Documentation/config.md)
+[replicate](https://gerrit.googlesource.com/plugins/replication/+doc/v2.15.4/src/main/resources/Documentation/config.md)
 to geographical mirrors for latency reduction and backup servers for hot
 spare redundancy.
 
 ## Extensible through plugins
 
 Gerrit Code Review can be extended and further customized by installing
-[server-side plugins](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15.3/config-plugins.html).
+[server-side plugins](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15.4/config-plugins.html).
 Source code for additional plugins can be found through the
 [project listing](https://gerrit.googlesource.com/plugins/).
 
diff --git a/pages/site/elasticsearch.md b/pages/site/elasticsearch.md
index 53dbdb5..7f214a6 100644
--- a/pages/site/elasticsearch.md
+++ b/pages/site/elasticsearch.md
@@ -15,7 +15,7 @@
 | 5.6.x                 | 2.14.8 or 2.15.3       |
 | 6.2.x                 | 2.14.8 or 2.15.3       |
 | 6.3.x                 | 2.14.10 or 2.15.3      |
-| 6.4.x                 | 2.14.12                |
+| 6.4.x                 | 2.14.12 or 2.15.4      |
 
 Note that although Elasticsearch 2.4.x is supported, we do not recommend using
 such an old version.
diff --git a/pages/site/releases/2.15.md b/pages/site/releases/2.15.md
index 5c89606..3a9f7b3 100644
--- a/pages/site/releases/2.15.md
+++ b/pages/site/releases/2.15.md
@@ -6,12 +6,14 @@
 toc: true
 ---
 
-Download: **[2.15.3](https://gerrit-releases.storage.googleapis.com/gerrit-2.15.3.war)**
+Download: **[2.15.4](https://gerrit-releases.storage.googleapis.com/gerrit-2.15.4.war)**
+| [2.15.3](https://gerrit-releases.storage.googleapis.com/gerrit-2.15.3.war)
 | [2.15.2](https://gerrit-releases.storage.googleapis.com/gerrit-2.15.2.war)
 | [2.15.1](https://gerrit-releases.storage.googleapis.com/gerrit-2.15.1.war)
 | [2.15](https://gerrit-releases.storage.googleapis.com/gerrit-2.15.war)
 
-Documentation: **[2.15.3](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15.3/index.html)**
+Documentation: **[2.15.4](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15.4/index.html)**
+| [2.15.3](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15.3/index.html)
 | [2.15.2](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15.2/index.html)
 | [2.15.1](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15.1/index.html)
 | [2.15](https://gerrit-documentation.storage.googleapis.com/Documentation/2.15/index.html)
@@ -389,7 +391,7 @@
 
 * Update Soy to 2017-04-23
 
-### 2.15.4 (in development)
+### 2.15.4
 
 * [Issue 7053](https://bugs.chromium.org/p/gerrit/issues/detail?id=7053):
 Modify search autocompletion to include only email.