Do not force converting 'params' values to string

Patch with replacing "u'" to "'" forces converting all 'params:'
values to string. This lead to converting dicts to
an OrderedDict object that become a string when Salt stores
the rendered file:

1. Source data for reclass.storage:

parameters:
  reclass:
    storage:
      node:
        infra_kvm_node01:
          params:
            example_dict:
              first_key: 1
              second_key: 2
            example_unicode: u'string'

2. Current result, 'reclass' reads 'example_dict' value
as a string "OrderedDict([..." and pass it to Salt pillar:

parameters:
  _param:
    example_dict: OrderedDict([('first_key', 1), ('second_key', 2)])
    example_unicode: 'string'

3. This patch apply 'replace' only for string objects, keeping other
objects as is, so the dict value will work fine:

parameters:
  _param:
    example_dict: {'first_key': 1, 'second_key': 2}
    example_unicode: 'string'

Change-Id: Ib11e5a14168941d528d7d506401813e2fb9b8ead
diff --git a/reclass/files/node.yml b/reclass/files/node.yml
index 25a190e..9b9c3c9 100644
--- a/reclass/files/node.yml
+++ b/reclass/files/node.yml
@@ -6,10 +6,18 @@
   {%- if node.params is defined or extra_params|length > 0 %}
   _param:
     {%- for param_name, param_value in node.params.iteritems() %}
+    {%- if param_value is not string %}
+    {{ param_name }}: {{ param_value }}
+    {%- else %}
     {{ param_name }}: {{ param_value|replace("u'", "'") }}
+    {%- endif %}
     {%- endfor %}
     {%- for param_name, param_value in extra_params.iteritems() %}
+    {%- if param_value is not string %}
+    {{ param_name }}: {{ param_value }}
+    {%- else %}
     {{ param_name }}: {{ param_value|replace("u'", "'") }}
+    {%- endif %}
     {%- endfor %}
   {%- endif %}
   {{ node.get('kernel', 'linux') }}: