Fix bug in python3 due to improper string handling
Fix bug in python3 due to improper string handling

jparyani/pycapnp,tempbottle/pycapnp,rcrowder/pycapnp,tempbottle/pycapnp,tempbottle/pycapnp,jparyani/pycapnp,jparyani/pycapnp,SymbiFlow/pycapnp,SymbiFlow/pycapnp,SymbiFlow/pycapnp,tempbottle/pycapnp,SymbiFlow/pycapnp,rcrowder/pycapnp,jparyani/pycapnp,rcrowder/pycapnp,rcrowder/pycapnp