tests: Clear cfg80211 scan results after wext_hidden

Leaving hidden SSIDs in the cfg80211 BSS table can result in errors in
the following test cases, so use special care to clear all BSS entries
at the end of the wext_hidden test case.

Signed-off-by: Jouni Malinen <j@w1.fi>

tests/hwsim/test_wext.py

@@ -212,10 +212,10 @@ def test_wext_scan_hidden(dev, apdev):
     if not wpas:
         return "skip"
 
-    hostapd.add_ap(apdev[0]['ifname'], { "ssid": "test-scan",
-                                         "ignore_broadcast_ssid": "1" })
-    hostapd.add_ap(apdev[1]['ifname'], { "ssid": "test-scan2",
-                                         "ignore_broadcast_ssid": "1" })
+    hapd = hostapd.add_ap(apdev[0]['ifname'], { "ssid": "test-scan",
+                                                "ignore_broadcast_ssid": "1" })
+    hapd2 = hostapd.add_ap(apdev[1]['ifname'], { "ssid": "test-scan2",
+                                                 "ignore_broadcast_ssid": "1" })
 
     id1 = wpas.connect("test-scan", key_mgmt="NONE", scan_ssid="1",
                        only_add_network=True)
@@ -232,6 +232,13 @@ def test_wext_scan_hidden(dev, apdev):
     id = wpas.connect("test-scan2", key_mgmt="NONE", scan_ssid="1",
                       only_add_network=True)
     wpas.connect_network(id, timeout=30)
+    wpas.request("DISCONNECT")
+    hapd2.disable()
+    hapd.disable()
+    wpas.interface_remove("wlan5")
+    wpas.interface_add("wlan5")
+    wpas.flush_scan_cache(freq=2412)
+    wpas.flush_scan_cache()
 
 def test_wext_rfkill(dev, apdev):
     """WEXT and rfkill block/unblock"""