Fix schema-to-template for empty schema

if schema is {}, the
schema_to_parameters_and_properties(schema)
function shouldn't get an error, and return
{}, {} for parameters and properties

Closes-Bug: #1341985

Change-Id: Ic206ba64811bf43080a9deebb7c3b4c19134c43d
Merge "Fix schema-to-template for empty schema"