vif_plug_ovs: clarify that the plugin was not in fact renamed

An earlier change claimed to be renaming the ovs plugin:

  commit 65ae52baa7
  Author: Sean Mooney <sean.k.mooney@intel.com>
  Date:   Fri May 20 20:43:14 2016 +0100

    This change renames the ovs plugin

On re-examination this was not in fact the case. The actual
name of the plugins is specified in the setup.cfg config
file "[entry_points]" section, which recorded the name as
"ovs". The bug fixed in 65ae52baa7
was simply that the 'describe' method was reporting the wrong
name, which has no functional impact on usage of the plugin.
It merely meant that any app relying on the introspection
data to identify available plugins would be told the wrong
name.

Change-Id: Iaf7c2e38bce809afc4801a3af0971977461d66d3

releasenotes/notes/fix-ovs-plugin-describe-049750609559f1ba.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - The OpenVSwitch plugin was registered with an entrypoint
+    name of "ovs", but its describe method mistakenly reported
+    that its name was "ovs_hybrid". The latter has been fixed
+    to match the registered name.

releasenotes/notes/rename-ovs-plugin-049750609559f1ba.yaml

@@ -1,5 +0,0 @@
----
-fixes:
-  - The ovs direct and ovs hybrid plug methods are now
-    handled by a single plugin. To reflect that the
-    ovs plugin has been renamed to 'ovs' from 'ovs_hybrid'