Fix AWS doc for macOS 10.11+ users.

Change-Id: I94e7a2f7bc441143640b24aa7984a5600bcd6740
Reviewed-on: https://asterix-gerrit.ics.uci.edu/1671
Sonar-Qube: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
BAD: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Till Westmann <tillw@apache.org>
diff --git a/asterixdb/asterix-doc/src/main/installation/aws.md b/asterixdb/asterix-doc/src/main/installation/aws.md
index 68c1428..cd7f4c7 100644
--- a/asterixdb/asterix-doc/src/main/installation/aws.md
+++ b/asterixdb/asterix-doc/src/main/installation/aws.md
@@ -58,6 +58,15 @@
          $ ansible --version
          ansible 2.2.1.0
 
+     **For users with macOS 10.11+**, please create a user-level Ansible configuration file at:
+
+         ~/.ansible.cfg
+
+     and add the following configuration:
+
+         [ssh_connection]
+         control_path = %(directory)s/%%C
+
   *  Download the AsterixDB distribution package, unzip it, navigate to `opt/aws/`
 
          $ cd opt/aws