Fixes jinja in include block

Some vars were missing {{ }}
Indentation was broken
isinstance is not available in Salt

salt/files/minion.d/f_defaults.conf

 #
 # Include a config file from some other path:
 {% if 'include' in cfg_minion -%}
-{%- do default_keys.append('include') %}
-    {% if isinstance(cfg_minion['include'], list) -%}
+{% do default_keys.append('include') -%}
+    {% if cfg_minion['include'] is iterable and cfg_minion['include'] is not string -%}
         include:
-        {% for include in cfg_minion['include'] -%}
+        {%- for include in cfg_minion['include'] %}
             - {{ include }}
-        {% endfor -%}
+        {%- endfor -%}
     {% else -%}
-        include: cfg_minion['include']
-    {% endif -%}
+        include: {{ cfg_minion['include'] }}
+    {%- endif -%}
 {% elif 'include' in cfg_salt -%}
-    {% if isinstance(cfg_salt['include'], list) -%}
+    {% if cfg_salt['include'] is iterable and cfg_salt['include'] is not string -%}
         include:
-        {% for include in cfg_salt['include'] -%}
+        {%- for include in cfg_salt['include'] %}
             - {{ include }}
-        {% endfor -%}
+        {%- endfor -%}
     {% else -%}
-        include: cfg_salt['include']
-    {% endif -%}
-{% endif -%}
+        include: {{ cfg_salt['include'] }}
+    {%- endif -%}
+{% endif %}
 
 #####   Minion module management     #####
 ##########################################