docs: update arcanist links

Summary:
I need a test commit for using arc.
This seems like an appropriate commit to use as a test

We may want to port this commit back to 3.7 also

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D11527

llvm-svn: 243408
diff --git a/llvm/docs/Phabricator.rst b/llvm/docs/Phabricator.rst
index 1dcd6a0..69bf3bf 100644
--- a/llvm/docs/Phabricator.rst
+++ b/llvm/docs/Phabricator.rst
@@ -162,6 +162,6 @@
 .. _LLVM's Phabricator: http://reviews.llvm.org
 .. _`http://reviews.llvm.org`: http://reviews.llvm.org
 .. _Code Repository Browser: http://reviews.llvm.org/diffusion/
-.. _Arcanist Quick Start: http://www.phabricator.com/docs/phabricator/article/Arcanist_Quick_Start.html
-.. _Arcanist User Guide: http://www.phabricator.com/docs/phabricator/article/Arcanist_User_Guide.html
+.. _Arcanist Quick Start: https://secure.phabricator.com/book/phabricator/article/arcanist_quick_start/
+.. _Arcanist User Guide: https://secure.phabricator.com/book/phabricator/article/arcanist/
 .. _llvm-reviews GitHub project: https://github.com/r4nt/llvm-reviews/