Pin virtalenv to 1.10.1

1.11 will not work because of https://github.com/pypa/virtualenv/issues/521

Change-Id: Ie8201734045a4a559e0249a214e200983fe8bd17

modules/openstack_project/manifests/base.pp

@@ -53,7 +53,7 @@ class openstack_project::base(
 
   include pip
   package { 'virtualenv':
-    ensure   => latest,
+    ensure   => '1.10.1',
     provider => pip,
     require  => Class['pip'],
   }