Make usage of new PHP_FE_END macro by felipe

http://svn.php.net/viewvc/php/php-src/trunk/ext/interbase/interbase.c?r1=308618&r2=313663

003 test now passes
Replace FIELD with CONSTANT (that is the alias returned in Firebird
stable 2.5.x )

http://svn.php.net/viewvc/php/php-src/trunk/ext/interbase/tests/003.phpt?r1=313664&r2=313669
http://svn.php.net/viewvc/php/php-src/trunk/ext/interbase/tests/003.phpt?revision=313669&view=markup

weird that in flamerobin it returns CONSTANT, CONSTANT ....
and in php CONSTANT, CONSTANT01

maybe it should be CONSTANT00, CONSTANT01
but for the moment i have silenced the error , I will see if needs to be patched