Remove executable bits from Python scripts

We can't use a single shebang:
* on some platforms `python` may mean Python 2, on others - Python 3
* on some platforms `python3` does not exist at all

Therefore, we're removing the shebangs altogether.

diff --git a/bin/lesson_check.py b/bin/lesson_check.py
old mode 100755 (executable)
new mode 100644 (file)

diff --git a/bin/lesson_initialize.py b/bin/lesson_initialize.py
old mode 100755 (executable)
new mode 100644 (file)

diff --git a/bin/repo_check.py b/bin/repo_check.py
old mode 100755 (executable)
new mode 100644 (file)

diff --git a/bin/test_lesson_check.py b/bin/test_lesson_check.py
old mode 100755 (executable)
new mode 100644 (file)

diff --git a/bin/workshop_check.py b/bin/workshop_check.py
old mode 100755 (executable)
new mode 100644 (file)