Fix a broken link. Patch by Nikola Smiljanic.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155139 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/UsersManual.html b/docs/UsersManual.html
index b33ed61..e9af769 100644
--- a/docs/UsersManual.html
+++ b/docs/UsersManual.html
@@ -1135,7 +1135,7 @@
 <li><tt>some_directory/bin/../include</tt></li>
 </ul>
 
-<p>This directory layout is standard for any toolchain you will find on the official <a href="mingw-w64.sourceforge.net">MinGW-w64 website</a>.
+<p>This directory layout is standard for any toolchain you will find on the official <a href="http://mingw-w64.sourceforge.net">MinGW-w64 website</a>.
 
 <p>Clang expects the GCC executable &quot;gcc.exe&quot; compiled for i686-w64-mingw32 (or x86_64-w64-mingw32) to be present on PATH.</p>