Fixing method remove_excess_vms

Before this fix, if the pool had an excessive number of 'pending' vms,
but was not full of 'ready' vms, we would end up clearing all the
'pending' vms regardless, which could bring us back under the max
pool size. This fix makes sure we only remove the excess, see
unit test for an example

lib/vmpooler/pool_manager.rb

@@ -631,8 +631,10 @@ module Vmpooler
                 move_vm_queue(pool['name'], next_vm, 'ready', 'completed')
               end
               if total > ready
-                $redis.smembers("vmpooler__pending__#{pool['name']}").each do |vm|
+                max_to_remove = total - pool['size']
+                $redis.smembers("vmpooler__pending__#{pool['name']}").each_with_index do |vm, i|
                   move_vm_queue(pool['name'], vm, 'pending', 'completed')
+                  if max_to_remove == (i+1) then break end
                 end
               end
             end

spec/unit/pool_manager_spec.rb

@@ -1669,9 +1669,20 @@ EOT
 
         subject.remove_excess_vms(config[:pools][0], provider, 2, 5)
       end
+
+      it 'should remove excess pending vms, but only the excess' do
+        create_pending_vm(pool,'vm1')
+        create_pending_vm(pool,'vm2')
+        create_pending_vm(pool,'vm3')
+        create_pending_vm(pool,'vm4')
+        expect(subject).to receive(:move_vm_queue).exactly(3).times
+
+        subject.remove_excess_vms(config[:pools][0], provider, 1, 5)
       end
     end
 
+  end
+
   describe 'prepare_template' do
     let(:mutex) { Mutex.new }
     let(:config) { YAML.load(<<-EOT