Add CONFIG_ROAMING option (off by default)

Change-Id: I846edd8a48e6c5e948732f28caf821055490d320
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
diff --git a/wpa_supplicant/events.c b/wpa_supplicant/events.c
index 812cd52..26e355e 100644
--- a/wpa_supplicant/events.c
+++ b/wpa_supplicant/events.c
@@ -837,6 +837,7 @@
 	if (!current_bss)
 		return 1; /* current BSS not seen in scan results */
 
+#ifdef CONFIG_ROAMING
 	wpa_dbg(wpa_s, MSG_DEBUG, "Considering within-ESS reassociation");
 	wpa_dbg(wpa_s, MSG_DEBUG, "Current BSS: " MACSTR " level=%d",
 		MAC2STR(current_bss->bssid), current_bss->level);
@@ -871,6 +872,9 @@
 	}
 
 	return 1;
+#else
+	return 0;
+#endif
 }
 
 /* Return < 0 if no scan results could be fetched. */