Change the path of pg_crc.h to follow the PostgreSQL code change.
Change the path of pg_crc.h to follow the PostgreSQL code change.

Since the following commit in Postgres upstream, pg_crc.h is move
from utils to common:
commit: c619c2351f7ec429b6ddce519c939f7b8465d711
author: Heikki Linnakangas heikki.linnakangas@iki.fi
date: Mon, 9 Feb 2015 11:17:56 +0200
Move pg_crc.c to src/common, and remove pg_crc_tables.h

This patch was created by Michael Paquier.
I add PG_VERSION_NUM if-def check temporarily.

bwtakacy/prev_pg_rman_repo,bwtakacy/prev_pg_rman_repo