Adding a deepcopy of the template before stack create validation

Calling stack.validate will modify the stack's template, which
we don't want to do.  We just want to validate the template and move
on with an already parsed template.

heat/engine/manager.py

@@ -124,6 +124,18 @@ class EngineManager(manager.Manager):
             return {'Error': 'Stack already exists with that name.'}
 
         metadata_server = config.FLAGS.heat_metadata_server_url
+        # We don't want to reset the stack template, so we are making
+        # an instance just for validation.
+        template_copy = deepcopy(template)
+        stack_validator = parser.Stack(stack_name, template_copy, 0, params,
+                             metadata_server=metadata_server)
+        response = stack_validator.validate()
+        stack_validator = None
+        template_copy = None
+        if 'Malformed Query Response' in \
+                response['ValidateTemplateResult']['Description']:
+            return response['ValidateTemplateResult']['Description']
+
         stack = parser.Stack(stack_name, template, 0, params,
                              metadata_server=metadata_server)
         rt = {}

heat/tests/__init__.py

@@ -21,8 +21,6 @@ import os
 import shutil
 
 from heat.db.sqlalchemy.session import get_engine
-import pdb
-
 
 def reset_db():
     if os.path.exists('heat-test.db'):