[gnome-builder] vala: pass cancellable to code copmletion operation

[Christian Hergert <chergert src gnome org>]

commit 20e0f6e5f06aa638cd54e020bafe75e4b1fc1efb
Author: Christian Hergert <christian hergert me>
Date:   Wed Oct 14 17:52:56 2015 -0700

    vala: pass cancellable to code copmletion operation
    
    How'd I miss this?

 .../vala-pack/ide-vala-completion-provider.vala    |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/plugins/vala-pack/ide-vala-completion-provider.vala 
b/plugins/vala-pack/ide-vala-completion-provider.vala
index df184f2..499d570 100644
--- a/plugins/vala-pack/ide-vala-completion-provider.vala
+++ b/plugins/vala-pack/ide-vala-completion-provider.vala
@@ -83,7 +83,7 @@ namespace Ide
                                                   line,
                                                   unsaved_files,
                                                   this,
-                                                  null,
+                                                  cancellable,
                                                   (obj,res) => {
                                int res_line = -1;
                                int res_column = -1;