Updated berkshelf to 3.1.5

Updated berkshelf from 2.0.18 to 3.1.5 in Gemfile and added supermarket source to Berksfile

Change-Id: I7d1f047ef1e7774ce112d6923aa02cfe25f5cea4
Implements: blueprint update-berkshelf

Berksfile

@@ -1,4 +1,6 @@
+source "https://supermarket.getchef.com"
+
 metadata
 
 cookbook "openstack-common",
-  git: "git://github.com/stackforge/cookbook-openstack-common.git"
+  github: "stackforge/cookbook-openstack-common"

CHANGELOG.md

@@ -4,6 +4,7 @@ This file is used to list changes made in each version of cookbook-openstack-ops
 
 ## 10.0.0
 * Upgrading to Juno
+* Upgrading berkshelf from 2.0.18 to 3.1.5
 
 ## 9.0.1
 ### Bug

Gemfile

@@ -3,7 +3,7 @@ source 'https://rubygems.org'
 
 gem 'chef', '~> 11.12.0'
 gem 'json', '<= 1.7.7' # chef 11 dependency
-gem 'berkshelf', '~> 2.0.18'
+gem 'berkshelf', '~> 3.1.5'
 gem 'hashie', '~> 2.0'
 gem 'chefspec', '~> 4.0.0'
 gem 'rspec', '~> 3.0.0'

TESTING.md

@@ -11,7 +11,7 @@ To run all of the tests with Strainer:
 Or you may run the tests individually:
 
     $ bundle install --path=.bundle # install gem dependencies
-    $ bundle exec berks install --path=.cookbooks # install cookbook dependencies
+    $ bundle exec berks vendor .cookbooks # install cookbook dependencies and create the folder .cookbooks
     $ bundle exec strainer test -s Strainerfile # run tests
 
 ## Rubocop  ##