Update file.sls

added possibility to delete files

linux/system/file.sls

 {%- for file_name, file in system.file.items() %}
 
 linux_file_{{ file_name }}:
-{%- if file.serialize is defined %}
+{%- if file.absent is defined and file.absent is sameas true %}
+  file.absent:
+
+{%- elif file.serialize is defined %}
   file.serialize:
     - formatter: {{ file.serialize }}
   {%- if file.contents is defined  %}
   {%- elif file.contents_pillar is defined %}
     - dataset_pillar: {{ file.contents_pillar }}
   {%- endif %}
+
 {%- else %}
   file.managed:
     {%- if file.source is defined %}
     {%- if file.encoding is defined %}
     - encoding: {{ file.encoding }}
     {%- endif %}
- 
+
 {%- endfor %}
 
 {%- endif %}