Revert "Create a new state file "PROFILE_NAME" (in replacement for netcfg's interface/ directory)."

This reverts commit 980d7169bf4336ff0f41839c8fbf8132155a978b.
A better way to compensate for absence of "interfaces/" state directory: read profile from wpa_supplicant.

Use a wpa_call status to retrieve the data associated with the
interface; then use field id_str.