Julian Oes 18dd6923e6 integrationtests: use Python2 for dependencies
This changes the shebang of the integration test files to python2
because the scripts fail on systems with Python 3 as the default.

Even though ROS has been ported to Python 3, there are still some
dependencies not playing along.

The error that comes up when starting with Python 3 is:
> No module named 'mavexpression'
2016-12-15 00:10:57 +01:00
..
2016-07-01 11:44:37 +02:00