Fix integration test shebangs and update tests.

* Integration tests now have their own list of allowed shebangs.
* Use `#!/usr/bin/env bash` instead of `#!/bin/bash`
  since the location is different on various platforms.

test/integration/targets/inventory_foreman_script/foreman.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Wrapper to use the correct Python interpreter and support code coverage.
 
 REL_SCRIPT="../../../../contrib/inventory/foreman.py"

test/integration/targets/vault/runme_change_pip_installed.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # start by removing pycrypto and cryptography