Added proper copyright notice into 9.6 docs

Author: vbwagner

doc/src/sgml/legal.sgml

@@ -10,6 +10,11 @@
 <legalnotice id="legalnotice">
  <title>Legal Notice</title>
 
+ <para>
+  <productname>Postgres Pro</productname> is Copyright &copy; 2016-2017
+  by the Postgres Professional.
+ </para>
+
  <para>
   <productname>PostgreSQL</productname> is Copyright &copy; 1996-2017
   by the PostgreSQL Global Development Group.