Fix vm clone problem when a Guid instance is passed as the instance_uuid

Without this patch the vm_clone requiest would not find a Managed Object
Reference when a UUID that is not a string is passed as the
instance_uuid option.  This is a problem because an unhelpful "undefined
method `parent' for nil:NilClass" would be thrown to the application.

This patch throws a more helpful Fog::Compute::Vsphere::NotFound
exception if the Virtual Machine template is not found.

The tests have been updated to reflect this expectation.

lib/fog/vsphere/requests/compute/vm_clone.rb

@@ -25,9 +25,11 @@ module Fog
           # Option handling
           options = vm_clone_check_options(options)
 
+          notfound = lambda { raise Fog::Compute::Vsphere::NotFound, "Cloud not find VM template" }
+
           # REVISIT: This will have horrible performance for large sites.
           # Find the Managed Object reference of the template VM (Wish I could do this with the API)
-          vm_mob_ref = list_all_virtual_machine_mobs.find do |vm|
+          vm_mob_ref = list_all_virtual_machine_mobs.find(notfound) do |vm|
             convert_vm_mob_ref_to_attr_hash(vm)['instance_uuid'] == options['instance_uuid']
           end
 
@@ -79,6 +81,10 @@ module Fog
         def vm_clone(options = {})
           # Option handling
           options = vm_clone_check_options(options)
+          notfound = lambda { raise Fog::Compute::Vsphere::NotFound, "Cloud not find VM template" }
+          vm_mob_ref = list_virtual_machines['virtual_machines'].find(notfound) do |vm|
+            vm['instance_uuid'] == options['instance_uuid']
+          end
           {
             'vm_ref'   => 'vm-123',
             'task_ref' => 'task-1234'

tests/vsphere/requests/compute/vm_clone_tests.rb

@@ -1,4 +1,5 @@
 Shindo.tests("Fog::Compute[:servers] | vm_clone request") do
+  require 'guid'
   template = "50323f93-6835-1178-8b8f-9e2109890e1a"
   compute = Fog::Compute[:vsphere]
 
@@ -15,5 +16,8 @@ Shindo.tests("Fog::Compute[:servers] | vm_clone request") do
            'it should raise ServiceError if a VM already exists with the provided name') do
       compute.vm_clone('instance_uuid' => '123', 'name' => 'jefftest')
     end
+    raises(Fog::Compute::Vsphere::NotFound, 'it should raise Fog::Compute::Vsphere::NotFound when the UUID is not a string') do
+      compute.vm_clone('instance_uuid' => Guid.from_s(template), 'name' => 'jefftestfoo')
+    end
   end
 end