fix apt repository setup

Closes #17

Signed-off-by: Sebastien Goasguen <runseb@gmail.com>
diff --git a/source/building_from_source.rst b/source/building_from_source.rst
index 29a379f..56f03e4 100644
--- a/source/building_from_source.rst
+++ b/source/building_from_source.rst
@@ -273,7 +273,7 @@
 
 .. sourcecode:: bash
 
-   deb http://server.url/cloudstack/repo binary ./
+   deb http://server.url/cloudstack/repo/binary ./
 
 Now that you have the repository info in place, you'll want to run
 another update so that APT knows where to find the CloudStack packages.