[gnome-boxes] Constructors of abstract classes should not be public

[Rico Tzschichholz <ricotz src gnome org>]

commit ec9ce6f88de60ae74f21e26f960f2b0c077f8b78
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Mar 18 10:13:08 2019 +0100

    Constructors of abstract classes should not be public

 src/machine.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/machine.vala b/src/machine.vala
index 77ec6c10..60b3def6 100644
--- a/src/machine.vala
+++ b/src/machine.vala
@@ -254,7 +254,7 @@ protected void show_display () {
         cr.fill ();
     }
 
-    public Machine (Boxes.CollectionSource source, string name, string? uuid = null) {
+    protected Machine (Boxes.CollectionSource source, string name, string? uuid = null) {
         this.name = name;
         this.source = source;
         this.connecting_cancellable = new Cancellable ();