Fix cu1 column selection logic in latex drawer (#2389)
Fix cu1 column selection logic in latex drawer (#2389)

* Fix cu1 column selection logic in latex drawer

When #1977 when we reworked the latex drawer to use layers and use
justification the implementation for the cu1 was not updated correctly.
In the previous implementation while iterating over the circuits it
when drawing a cu1 it would increment the columns parameter before
drawing (it had to do with the different technique for tracking
occupied positions on the xy matrix used for drawing the circuit see
[1] for more details). So when we drew the cu1 the column index would
be where we put the \\dstick and we'd want to put the \\ctrl and
\\control one column behind the current value. But now with iterating
over layers now this is isn't the case and the column index is the
current position. So the logic needs to be reversed and we want to use
the current column as the location for \\ctrl and \\control and the
next column as the location for \\dstick. This commit corrects this
change so we draw cu1s properly and don't overwrite previously written
gates.

Fixes #2388

[1] https://github.com/Qiskit/qiskit-terra/blob/0.7/qiskit/tools/visualization/_latex.py#L738-L741

* Updated the columns variable so that gates can be more than one column wide

* Fix lint

QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py