Fix a parameter of Ignis in requirements.txt and setup.py

[t-imamichi]

Summary

According to Ignis readme I added '[cvx]' option to ignis.

Fixes #1073

Details and comments

Without cvxpy, import qiskit.aqua fails. See #1073.

[t-imamichi]

Should I add a unit test to check qiskit.aqua.__version__?

[mtreinish]

This is the not the correct fix, we do not want to require cvxpy as a requirement for aqua or ignis or qiskit in general (see #1055 ). This is just a temporary issue because of a bug in ignis 0.3.2 see qiskit-community/qiskit-ignis#429 I'm preparing a 0.3.3 release right now to fix this

[mtreinish]

That being said I think we should add a unit test like you proposed to the meta repository to catch this kind of bug sooner before we bump the metapackage. The integration testing in https://github.com/Qiskit/qiskit/blob/master/test/test_metapackage.py before we push out a new combined release is severely lacking.

[t-imamichi]

@mtreinish Thank you for your information. I will close this PR because it is fixed at Ignis side.
Is it a good idea to add the following test to test_metapackages.py?

def test_aqua_import_works(self):
        """Test importing Aqua"""
        self.assertIsNotNone(qiskit.aqua)

[mtreinish]

@mtreinish Thank you for your information. I will close this PR because it is fixed at Ignis side.
Is it a good idea to add the following test to test_metapackages.py?

def test_aqua_import_works(self):
        """Test importing Aqua"""
        self.assertIsNotNone(qiskit.aqua)

Yeah, I like that idea, we probably should add a test like that for each element to the file. Also maybe a test that verifies there is a version for each element in the qiskit.__qiskit_version__