Move vip conditional logic from stemcell impl to spec helpers.

Previously, we were following the existing approach of using the
stemcell name to determine whether we support certain features. Now,
we're moving towards making the stemcell implementation agnostic to
these details, by refactoring the conditional logic to determine whether
vip networking is supported out into the spec helpers.

[#106771316](https://www.pivotaltracker.com/story/show/106771316)

Signed-off-by: Wagner Camarao <wcamarao@vmware.com>

lib/bat/deployment_helper.rb

@@ -129,6 +129,10 @@ def static_ip
       static_ips.first
     end
 
+    def includes_vip?
+      !!(@spec['properties']['vip'])
+    end
+
     def vip
       @spec['properties']['vip']
     end

lib/bat/stemcell.rb

@@ -63,10 +63,6 @@ def supports_raw_ephemeral_storage?
       name =~ /aws/
     end
 
-    def supports_vip?
-      !!(name =~ /aws/ || name =~ /openstack/)
-    end
-
     def ==(other)
       to_s == other.to_s
     end

spec/bat/stemcell_spec.rb

@@ -110,23 +110,6 @@
     end
   end
 
-  describe '#supports_vip?' do
-    {
-      'bosh-openstack-kvm-centos-go_agent'        => true,
-      'bosh-openstack-kvm-ubuntu-trusty-go_agent' => true,
-      'bosh-aws-xen-ubuntu-trusty-go_agent'       => true,
-      'bosh-aws-xen-centos-7-go_agent'            => true,
-      'bosh-vsphere-esxi-ubuntu-trusty-go_agent'  => false,
-      'bosh-vsphere-esxi-centos-7-go_agent'       => false,
-      'bosh-vcloud-esxi-ubuntu-trusty-go_agent'   => false,
-    }.each do |stemcell_name, expected|
-      it "returns #{expected} for #{stemcell_name}" do
-        stemcell = Bat::Stemcell.new(stemcell_name, nil)
-        expect(stemcell.supports_vip?).to be(expected)
-      end
-    end
-  end
-
   describe '#to_s' do
     it 'returns "<name>-<version>"' do
       expect(stemcell.to_s).to eq('STEMCELL_NAME-STEMCELL_NAME')

spec/system/with_release_stemcell_spec.rb

@@ -123,7 +123,7 @@ def matchdata_to_h(matchdata)
     end
 
     it 'should have network access to the vm using the vip' do
-      skip "vip network isn't supported" unless @requirements.stemcell.supports_vip?
+      skip "vip network isn't supported" unless includes_vip?
 
       expect(vip).not_to be_nil
       expect(ssh(vip, 'vcap', '/sbin/ifconfig eth0', @our_ssh_options)).to match /#{static_ip}/