Update copyright for 2016

Backpatch certain files through 9.1

src/backend/optimizer/prep/prepjointree.c

@@ -12,7 +12,7 @@
  *		reduce_outer_joins
  *
  *
- * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *

src/backend/optimizer/prep/prepqual.c

@@ -19,7 +19,7 @@
  * tree after local transformations that might introduce nested AND/ORs.
  *
  *
- * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *

src/backend/optimizer/prep/prepsecurity.c

@@ -3,7 +3,7 @@
  * prepsecurity.c
  *	  Routines for preprocessing security barrier quals.
  *
- * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *

src/backend/optimizer/prep/preptlist.c

@@ -27,7 +27,7 @@
  * that because it's faster in typical non-inherited cases.
  *
  *
- * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION

src/backend/optimizer/prep/prepunion.c

@@ -17,7 +17,7 @@
  * append relations, and thenceforth share code with the UNION ALL case.
  *
  *
- * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *