idevice: Use more common "ERROR:" syntax for error messages
diff --git a/src/idevice.c b/src/idevice.c
index 593a2ae..3d20069 100644
--- a/src/idevice.c
+++ b/src/idevice.c
@@ -73,7 +73,7 @@
 	int res = usbmuxd_subscribe(usbmux_event_cb, user_data);
 	if (res != 0) {
 		event_cb = NULL;
-		debug_info("Error %d when subscribing usbmux event callback!", res);
+		debug_info("ERROR: usbmuxd_subscribe() returned %d!", res);
 		return IDEVICE_E_UNKNOWN_ERROR;
 	}
 	return IDEVICE_E_SUCCESS;
@@ -90,7 +90,7 @@
 	event_cb = NULL;
 	int res = usbmuxd_unsubscribe();
 	if (res != 0) {
-		debug_info("Error %d when unsubscribing usbmux event callback!", res);
+		debug_info("ERROR: usbmuxd_unsubscribe() returned %d!", res);
 		return IDEVICE_E_UNKNOWN_ERROR;
 	}
 	return IDEVICE_E_SUCCESS;