test_compiler breaks AerJob status check

[nonhermitian]

Informations

• Qiskit Terra version: master
• Python version:
• Operating system:

What is the current behavior?

When running the tests, the following does not work when run after the test_compiler module:

backend = Aer.get_backend('qasm_simulator')
job_sim = execute(qc, backend)
job_sim.status()

Traceback (most recent call last):
  File "/Users/paul/Desktop/Github_repos/qiskit-core/test/python/test_cpp.py", line 34, in test_aer_status
    job_sim.status()
  File "/Users/paul/Desktop/Github_repos/qiskit-core/qiskit/backends/aer/aerjob.py", line 37, in _wrapper
    return func(self, *args, **kwargs)
  File "/Users/paul/Desktop/Github_repos/qiskit-core/qiskit/backends/aer/aerjob.py", line 118, in status
    self.__class__.__name__))
qiskit.backends.joberror.JobError: 'Unexpected behavior of AerJob'

However, if run before that module, it works fine. This is true both when running locally and on Travis. This is blocking #975.

Steps to reproduce the problem

What is the expected behavior?

Suggested solutions

[atilag]

I'm taking over this one