This way, the wlan1 interface will only be created whenever a user wants to
bring the interface up with ifupdown. Modify the script to be able to delete
the interface whenever it gets brought down and remove its .sh file extension
so run-parts can run it properly during the ifup process.
https://jira.digi.com/browse/DEL-6353
Signed-off-by: Gabriel Valcazar <gabriel.valcazar@digi.com>