Bump ansible_tower_client version dependency

Bump Ansible Tower Client dependency to version 0.14. This version
includes a method to fetch last update stdout capture for an Ansible
project.

Gemfile

@@ -86,7 +86,7 @@ group :amazon, :manageiq_default do
 end
 
 group :ansible, :manageiq_default do
-  gem "ansible_tower_client",           "~>0.13.0",      :require => false
+  gem "ansible_tower_client",           "~>0.14.0",      :require => false
 end
 
 group :azure, :manageiq_default do