Fix wrong device disconnected detection

Currently ideviceinstaller hooked to event IDEVICE_DEVICE_REMOVE, but did not
check UDID, so it bailed out if a random idevice was disconnected.

Also added a message to indicate when a device is disconnected.
diff --git a/src/ideviceinstaller.c b/src/ideviceinstaller.c
index 12f2caf..5ff9dad 100644
--- a/src/ideviceinstaller.c
+++ b/src/ideviceinstaller.c
@@ -323,7 +323,10 @@
 static void idevice_event_callback(const idevice_event_t* event, void* userdata)
 {
 	if (event->event == IDEVICE_DEVICE_REMOVE) {
-		is_device_connected = 0;
+		if (!strcmp(udid, event->udid)) {
+			fprintf(stderr, "ideviceinstaller: Device removed\n");
+			is_device_connected = 0;
+		}
 	}
 }
 
@@ -657,6 +660,10 @@
 		return -1;
 	}
 
+	if (!udid) {
+		idevice_get_udid(phone, &udid);
+	}
+
 	if (LOCKDOWN_E_SUCCESS != lockdownd_client_new_with_handshake(phone, &client, "ideviceinstaller")) {
 		fprintf(stderr, "Could not connect to lockdownd. Exiting.\n");
 		goto leave_cleanup;