Fix scan_runs counting

Addition of the background scanning mechanism in commit
60b94c9819199c0427e623080ebae27fe44be6b5 moved the scan trigger
into a new function that was also incrementing the scan_runs
counter, but the removal of the previous scan_runs incrementation
was forgotten from that patch. This counter should only be updated
into a single location, so remove the old one. This improves AP
selection for WPS provisioning by not skipping some of the initial
scans.

wpa_supplicant/scan.c

@@ -431,8 +431,7 @@ static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
 		if (prev_state != wpa_s->wpa_state)
 			wpa_supplicant_set_state(wpa_s, prev_state);
 		wpa_supplicant_req_scan(wpa_s, 1, 0);
-	} else
-		wpa_s->scan_runs++;
+	}
 }