Fix IF NOT EXISTS in CREATE STATISTICS
I misplaced the IF NOT EXISTS clause in commit
7b504eb282, before the
word STATISTICS. Put it where it belongs.
Patch written independently by Amit Langote and myself. I adopted his
submitted test case with a slight edit also.
Reported-by: Bruno Wolff III
Discussion: https://postgr.es/m/
20170621004237.GB8337@wolff.to