Pin pip packages to stay with python2

Change-Id: Ibd3b9883130d57afbd7f6bacaecf7fec467996e7
Related-Prod: PROD-34533
diff --git a/src/com/mirantis/mk/Openstack.groovy b/src/com/mirantis/mk/Openstack.groovy
index 277d839..94fc663 100644
--- a/src/com/mirantis/mk/Openstack.groovy
+++ b/src/com/mirantis/mk/Openstack.groovy
@@ -41,7 +41,7 @@
         'oslo.i18n>=2.3.0,<2.4.0',
         'oslo.serialization>=1.8.0,<1.9.0',
         'oslo.utils>=1.4.0,<1.5.0',
-        'docutils'
+        'docutils==0.16'
     ]
 
     def openstack_latest_packages = [
@@ -54,9 +54,11 @@
         'cmd2<0.9.0;python_version=="2.7"',
         'cmd2>=0.9.1;python_version=="3.4"',
         'cmd2>=0.9.1;python_version=="3.5"',
-        'python-openstackclient',
-        'python-heatclient',
-        'docutils'
+        // NOTE: pin client packages to current latest to prevent
+        // downloading packages which are not support Python 2.7
+        'python-openstackclient==4.0.0',
+        'python-heatclient=1.18.0',
+        'docutils==0.16'
     ]
 
     if (version == 'kilo') {