Remove useless shebangs (open-telemetry#2135)

These files do not have the executable bit set in their filesystem
permissions (so the shebang line, `#!`, is useless), and they are not
script-like (do not have `if __name__ == "__main__"` or interesting
side-effects), so making them executable would not make sense.

Author: musicinmybrain

Diff for: instrumentation/opentelemetry-instrumentation-django/src/opentelemetry/instrumentation/django/middleware/sqlcommenter_middleware.py

@@ -1,5 +1,3 @@
-#!/usr/bin/python
-#
 # Copyright The OpenTelemetry Authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");

Diff for: opentelemetry-instrumentation/src/opentelemetry/instrumentation/auto_instrumentation/__init__.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python3
-
 # Copyright The OpenTelemetry Authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");

Diff for: opentelemetry-instrumentation/src/opentelemetry/instrumentation/bootstrap.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python3
-
 # Copyright The OpenTelemetry Authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");