Update arrayfire submodule to v3.4.2 tag

9prady9 · 9prady9 · commit d81faf84cb9f · 2017-06-16T11:33:01.000+05:30
diff --git a/arrayfire b/arrayfire
@@ -1 +1 @@
-Subproject commit 10d9716a4aca5bc413d642be6295ce08614d5c36
+Subproject commit 2da99675a12fd10f38cd5633a77c3d09e8070bbf
