[gnome-builder] Gradle: fix GradleBuildTarget

[Christian Hergert <chergert src gnome org>]

commit 245f1329bdbcef5570075814e1d22f46f4e652da
Author: Daniel Buch <boogiewasthere gmail com>
Date:   Mon Jan 21 08:43:12 2019 +0100

    Gradle: fix GradleBuildTarget
    
    Fixes #771

 src/plugins/gradle/gradle_plugin.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/plugins/gradle/gradle_plugin.py b/src/plugins/gradle/gradle_plugin.py
index b3a30dc68..99536d8a0 100755
--- a/src/plugins/gradle/gradle_plugin.py
+++ b/src/plugins/gradle/gradle_plugin.py
@@ -141,7 +141,7 @@ class GradleBuildTargetProvider(Ide.Object, Ide.BuildTargetProvider):
                                          code=Gio.IOErrorEnum.NOT_SUPPORTED))
             return
 
-        task.targets = [GradleBuildTarget(context=self.get_context())]
+        task.targets = [context.ensure_child_typed(GradleBuildTarget)]
         task.return_boolean(True)
 
     def do_get_targets_finish(self, result):