hostapd.sh: fix unexpected control interface socket removal

After wpa_supplicant_prepare_interface() there could be 3 cases:

• wpa_supplicant is (re-)started
• wpa_supplicant is not touched if config was not changed
• config reload is sent to wpa_supplicant if config was changed

In the last cases there is an issue that control interface socket is removed and not added back. Patch fixes these cases by below changes:

• do not remove control interface outside, as wpa_supplicant handles adding/removing it by itself
• pass control interface directory to the config file for proper reload case handling by wpa_supplicant