Update HACKING file.

This updates the hacking file to include notes about
openstack-common and update OpenStack LLC to the Openstack
Foundation

Change-Id: I2cee5f16b9e1f69ec5a44b76c4cc053cabfc9197
diff --git a/HACKING.rst b/HACKING.rst
index fed4130..a546f8c 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -153,10 +153,25 @@
                              kwarg2=dict_of_numbers)
 
 
+openstack-common
+----------------
+
+A number of modules from openstack-common are imported into the project.
+
+These modules are "incubating" in openstack-common and are kept in sync
+with the help of openstack-common's update.py script. See:
+
+  http://wiki.openstack.org/CommonLibrary#Incubation
+
+The copy of the code should never be directly modified here. Please
+always update openstack-common first and then run the script to copy
+the changes across.
+
+
 OpenStack Trademark
 -------------------
 
-OpenStack is a registered trademark of OpenStack, LLC, and uses the
+OpenStack is a registered trademark of the OpenStack Foundation, and uses the
 following capitalization:
 
    OpenStack