Change PostgreSQL default version from 9.2 to 9.3

An exp-run has been performed on this default version change, and both
pgsql and portmgr are aware of this change.  Note that PR originally
made the jump from 9.0 to 9.3, but a conservative change to 9.2 was
done in May instead.

PR:	187286


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@374256 35697150-7ecd-e111-bb59-0022644237b5