databases/php70-interbase: Allow creation of multiple connections to Interbase

Currently the first connection to the database is closed
when a second one is opened. This bug was already reported to upstream:
https://bugs.php.net/bug.php?id=72175

Reported by: Marc Muncke <m.muncke@computer1020.at>
Reviewed by: Marc Muncke <m.muncke@computer1020.at>
MFH: 2017Q1