Warn about lack of reclass in Salt pre-0.17

Signed-off-by: martin f. krafft <madduck@madduck.net>
diff --git a/doc/source/salt.rst b/doc/source/salt.rst
index 272dc71..ccf30bb 100644
--- a/doc/source/salt.rst
+++ b/doc/source/salt.rst
@@ -2,6 +2,20 @@
 Using reclass with Salt
 =======================
 
+.. warning::
+
+  The latest release of Salt, version 0.16.3, does *not yet* include the
+  reclass adapter. You could use the ``cmd_yaml`` adapters, but at least for
+  ``ext_pillar``, they are currently not useable, as they `do not export the
+  minion ID to the command they run`_.
+
+  Your best bet at this stage is to wait for Salt 0.17, or to run Salt from
+  a Git clone, `branch "develop"`_. Sorry about that.
+
+.. _do not export the minion ID to the command they run:
+   https://github.com/saltstack/salt/issues/2276
+.. _branch "develop": https://github.com/saltstack/salt/tree/develop
+
 Quick start
 -----------
 The following steps should get you up and running quickly with |reclass| and