Mathieu Servillat / ctools

The start time tstart was reused for the computation of the start time of the function execution, leading to invalid time intervals in the ctobssim step.

This command was run:
  autopep8 --select E101,W191 --in-place --recursive .

It fixes only these two issues:
  - W191 indentation contains tabs
  - E101 indentation contains mixed spaces and tabs