Tidying: Unify the shebang call in all convert scripts

Previously some scripts were calling env and bash, some were only calling bash.

This commit unifies the scripts to all use `#! /usr/bin/env bash`

Changelog: None

Signed-off-by: Ole Petter <ole.orhagen@northern.tech>

mender-convert

@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#! /usr/bin/env bash
 #
 # Copyright 2019 Northern.tech AS
 #

mender-convert-extract

@@ -1,4 +1,4 @@
-#!/bin/bash
+#! /usr/bin/env bash
 #
 # Copyright 2019 Northern.tech AS
 #

mender-convert-modify

@@ -1,4 +1,4 @@
-#!/bin/bash
+#! /usr/bin/env bash
 #
 # Copyright 2019 Northern.tech AS
 #

mender-convert-package

@@ -1,4 +1,4 @@
-#!/bin/bash
+#! /usr/bin/env bash
 #
 # Copyright 2019 Northern.tech AS
 #