Update Boost.Compute Submodule (#415)

Use the latest develop branch, which include a bug fix for Windows
2017-04-13 22:42:48 -07:00 · 2017-04-13 22:42:48 -07:00 · 9224a9d125
--- a/2
+++ b/2
@ -1 +1 @@
-Subproject commit 1380a04582080bbe2364352b336270bc4bfa3025
+Subproject commit 6de7f6448796f67958dde8de4569fb1ae649ee91