corrected a minor issue if parse_value is called incorrectly (normally, this should never happen).

Author: jacobwilliams

src/json_value_module.F90

@@ -9088,6 +9088,7 @@ recursive subroutine parse_value(json, unit, str, value)
         !the routine is being called incorrectly.
         if (.not. associated(value)) then
             call json%throw_exception('Error in parse_value: value pointer not associated.')
+            return
         end if
 
         ! pop the next non whitespace character off the file