remove open(status=) parameter, use action instead

The h%open(..., status=) parameter is DEPRECATED and is ignored. Its functionality was duplicated by the h%open(..., action=) parameter.

As before:

• h%open(...) defaults to action='rw', which opens or creates a file.
• action='w' erases an existing file if present.
• action='r+' or action='r' errors if file doesn't exist