Revert "enable json API by default (refs #2889)"
Revert "enable json API by default (refs #2889)"

This reverts commit 1e500295d1f1a9c50ef2f1b981e6b46097b7221a.

openpne/OpenPNE3,nise-nabe/ppcon-sns,openpne/OpenPNE3,tejima/OP3PKG,openpne/OpenPNE3,tejima/OP3PKG,openpne/OpenPNE3,nise-nabe/ppcon-sns