Fix JSON struct handler glue.
Fix JSON struct handler glue.

hntrmrrs/capnproto,MarPiRK/capnproto,ligzy/capnproto,pjulien/capnproto,hntrmrrs/capnproto,maurer/capnproto,martindale/capnproto,mrdomino/capnproto,MarPiRK/capnproto,bryce-gibson/capnproto,ligzy/capnproto,mrdomino/capnproto,rcrowder/capnproto,vladon/capnproto,bsn069/capnproto,nagyistoce/capnproto,nagyistoce/capnproto,kamalmarhubi/capnproto,bsn069/capnproto,vladon/capnproto,bsn069/capnproto,rcrowder/capnproto,joliss/capnproto,jparyani/capnproto,jparyani/capnproto,ligzy/capnproto,kamalmarhubi/capnproto,pjulien/capnproto,MarPiRK/capnproto,bryce-gibson/capnproto,ocdtrekkie/capnproto,martindale/capnproto,mologie/capnproto,mologie/capnproto,martindale/capnproto,kamalmarhubi/capnproto,maurer/capnproto,maurer/capnproto,nagyistoce/capnproto,mologie/capnproto,pjulien/capnproto,joliss/capnproto,jparyani/capnproto,bryce-gibson/capnproto,mrdomino/capnproto,hntrmrrs/capnproto,joliss/capnproto,ocdtrekkie/capnproto,ocdtrekkie/capnproto,vladon/capnproto,rcrowder/capnproto