Fix latex columns count (#3243)
Fix latex columns count (#3243)

The latex drawer uses a class attribute img_depth to keep track of the
number of columns to put in the output img_depth (along with some other
things related to that). This value was attempted to be figured out by
looking at the number of layers except if there is a cu1 gate in a
layer then that layer has 2 columns (because the label takes up one).
However this count was done incorrectly and instead the number of
columns was equivalent to the number of gates in each layer plus 2
columns for each cu1. This resulted in a huge empty space for circuits
with lots of qubits, especially if they had lots of gates per layer.
This commit corrects the layer count loop to instead properly only
count a layer once and twice if it has a cu1 gate in the layer.

Fixes #3232
QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py