[www] Update analyzer release notes to correct the checker-278 build date.

This is not the future.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@259969 91177308-0d34-0410-b5e6-96231b3b80d8

www/analyzer/release_notes.html

@@ -15,7 +15,7 @@
 
 <h1>Release notes for <tt>checker-XXX</tt> builds</h1>
 <h4 id="checker_278">checker-278</h4>
-<p><b>built:</b> February 6, 2016</br>
+<p><b>built:</b> February 5, 2016</br>
 	<b>download:</b> <a href="downloads/checker-278.tar.bz2">checker-278.tar.bz2</a></p>
 	<p><b>highlights:</b></p>
 	<ul>