DOC: fixed copyrights and removed legal notice

Author: Liudmila Mantrova

doc/src/sgml/legal.sgml

@@ -6,8 +6,12 @@
  <year>1996-2018</year>
  <holder>The PostgreSQL Global Development Group</holder>
 </copyright>
+<copyright>
+ <year>2015-2018</year>
+ <holder>Postgres Professional</holder>
+</copyright>
 
-<legalnotice id="legalnotice">
+<!-- legalnotice id="legalnotice">
  <title>Legal Notice</title>
 
  <para>
@@ -47,4 +51,4 @@
   UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  </para>
 
-</legalnotice>
+</legalnotice -->