Use "python -m coverage" rather than use "coverage" explicitly

When coverage module is installed using a package from Debian/Ubuntu,
the command name is "python-coverage". By using "python -m coverage"
the coverage module is detected in both cases.

Change-Id: Icf9084855b83d0cc721de5325f38cf72ac85ff81
Closes-Bug: #1241332
Co-Authored-By: florent <florent.flament-ext@cloudwatt.com>
Merge "Use "python -m coverage" rather than use "coverage" explicitly"