Fix ext/pgsql builds with libpq < 7.3.

Fixes bug #67550 (Error in code "form" instead of "from", pgsql.c, line 756).
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  Fix ext/pgsql builds with libpq < 7.3.
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Fix ext/pgsql builds with libpq < 7.3.
Merge branch 'PHP-5.6'

* PHP-5.6:
  Fix ext/pgsql builds with libpq < 7.3.
NEWS block for 5.6.0RC3
Merge branch 'PHP-5.6'

* PHP-5.6:
  NEWS block for 5.6.0RC3
Merge branch 'master' of git://github.com/php/php-src