Make ListOp.num_qubits check all ops for same num_qubits (Qiskit/qiskit-aqua#1189)
Make ListOp.num_qubits check all ops for same num_qubits (Qiskit/qiskit-aqua#1189)

* Make ListOp.num_qubits check all ops for same num_qubits

Previously, the number of qubits in the first operator in the ListOp
was returned. With this change, an additional check is made that all
other operators also have the same number of qubits.

Closes Qiskit/qiskit-aqua#1086

* Add release note for listop-check-num-qubits

Co-authored-by: Manoel Marques <ea0e1aac252908b77f7a6302e9c3d004f36f7b3f@ibm.com>
QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py