docs: update calendar, add news item and link release notes for 17.1.9

Signed-off-by: Andres Gomez <agomez@igalia.com>

docs/index.html

@@ -16,6 +16,12 @@
 
 <h1>News</h1>
 
+<h2>September 8, 2017</h2>
+<p>
+<a href="relnotes/17.1.9.html">Mesa 17.1.9</a> is released.
+This is a bug-fix release.
+</p>
+
 <h2>September 4, 2017</h2>
 <p>
 <a href="relnotes/17.2.0.html">Mesa 17.2.0</a> is released.  This is a

docs/release-calendar.html

@@ -39,13 +39,7 @@ if you'd like to nominate a patch in the next stable release.
 <th>Notes</th>
 </tr>
 <tr>
-<td rowspan="2">17.1</td>
-<td>2017-09-08</td>
-<td>17.1.9</td>
-<td>Andres Gomez</td>
-<td></td>
-</tr>
-<tr>
+<td>17.1</td>
 <td>2017-09-22</td>
 <td>17.1.10</td>
 <td>Juan A. Suarez Romero</td>

docs/relnotes.html

@@ -21,6 +21,7 @@ The release notes summarize what's new or changed in each Mesa release.
 </p>
 
 <ul>
+<li><a href="relnotes/17.1.9.html">17.1.9 release notes</a>
 <li><a href="relnotes/17.2.0.html">17.2.0 release notes</a>
 <li><a href="relnotes/17.1.8.html">17.1.8 release notes</a>
 <li><a href="relnotes/17.1.7.html">17.1.7 release notes</a>