Remove version from patches directory

This patch still applies against Nova master, so it's not
actually specific to kilo.  To avoid confusion, let's just name the
directory "nova".  If it merge conflicts at some point we can add
version-specific ones again.

README.rst

@@ -27,7 +27,7 @@ cloud Nova.  Examples:
 
 TripleO/RDO::
 
-    sudo cp patches/kilo/nova-pxe-boot.patch /usr/lib/python2.7/site-packages/nova
+    sudo cp patches/nova/nova-pxe-boot.patch /usr/lib/python2.7/site-packages/nova
     cd /usr/lib/python2.7/site-packages/nova
     sudo patch -p1 < nova-pxe-boot.patch
 
@@ -44,7 +44,7 @@ Devstack:
 
    ::
 
-      cp patches/kilo/nova-pxe-boot.patch /opt/stack/nova
+      cp patches/nova/nova-pxe-boot.patch /opt/stack/nova
       cd /opt/stack/nova
       patch -p1 < nova-pxe-boot.patch