(maint) Remove instance during acceptance tests

Previously during the sqlserver_config acceptance tests multiple database
instances were being created, instead of destroyed, for example a datbase
instance of 'abseny' was being created.  This commit fixes this test fixture
failure by calling the ensure_sqlserver_instance helper method with the correct
parameters to remove an instance.

Author: glennsarti

spec/acceptance/sqlserver_config_spec.rb

@@ -46,7 +46,7 @@ def ensure_sqlserver_instance(inst_name, ensure_val = 'present')
 
     after(:all) do
       # remove the newly created instance
-      ensure_sqlserver_instance('absent')
+      ensure_sqlserver_instance(inst_name, 'absent')
     end
 
     it 'Create New Admin Login:', :tier_low => true do