Add support for Vmware 6.7 (#70)

* Add support for Vmware 6.7

Co-Authored-By: Paul Angus <paul.angus@shapeblue.com>
diff --git a/source/releasenotes/compat.rst b/source/releasenotes/compat.rst
index ef373df..37e96a7 100644
--- a/source/releasenotes/compat.rst
+++ b/source/releasenotes/compat.rst
@@ -48,7 +48,9 @@
 
    .. note:: It is now required to enable HA on the XenServer pool in order to recover from a pool-master failure. Please refer to the `XenServer documentation <http://docs.vmd.citrix.com/XenServer/6.5.0/1.0/en_gb/>`_.
 
--  VMware versions 5.0 Update 3, 5.1 Update 3, 5.5 Update 3b, 6.0 Update 2, and 6.5 GA
+-  VMware versions 5.0, 5.1, 5.5, 6.0, 6.5 and 6.7
+   .. note:: There is a known issue in 6.7u1 (https://kb.vmware.com/s/article/67315) which blocks some 
+      CloudStack cloning operations. The use of linked clones is known to be effected.
 -  LXC Host Containers on RHEL 7
 -  Windows Server 2012 R2 (with Hyper-V Role enabled)
 -  Hyper-V 2012 R2