add missing to_bytes import in interfaces_file

lib/ansible/modules/system/interfaces_file.py

@@ -150,7 +150,7 @@ import re
 import tempfile
 
 from ansible.module_utils.basic import AnsibleModule
-
+from ansible.module_utils._text import to_bytes
 
 def lineDict(line):
     return {'line': line, 'line_type': 'unknown'}