(PUP-6774) Fix incorrect call to is_json_type in Puppet::Resource

[whopper]

The actual method name is is_json_type?

[whopper]

Verified environment/variables_refreshed_each_compilation.rb now passes:

      Test Suite: tests @ 2016-10-04 13:30:43 -0700

      - Host Configuration Summary -


              - Test Case Summary for suite 'tests' -
       Total Suite Time: 79.89 seconds
      Average Test Time: 79.89 seconds
              Attempted: 1
                 Passed: 1
                 Failed: 0
                Errored: 0
                Skipped: 0
                Pending: 0
                  Total: 1

      - Specific Test Case Status -

Beaker completed successfully, thanks.

[whopper]

/cc @hlindberg or @thallgren, this will un-break CI

[MosesMendoza]

👍

[branan]

Since this didn't get caught by unit tests, it seems like we might have a test coverage gap - is that something that should be fixed either in this or in another PR soon-ish?

[whopper]

@branan makes sense - I'd vote for a followup PR as this is just intended as an immediate fix to get CI passing again

[branan]

@whopper I'm cool with that