When JSON model's no_paramfile attribute is given, check for its value

Before this fix, only existance of no_paramfile attribute was checked and
its value(true/false) was not checked.
So, as long as no_paramfile attribute was defined in JSON model,
"no_paramfile": true and "no_paramfile": false behaved the same way.
Merge branch 'quiver-fix-no_paramfile-json-model' into develop

Closes #687

* quiver-fix-no_paramfile-json-model:
  When JSON model's no_paramfile attribute is given, check for its value