skin_parser Reduce ram usage for conditionals on %ft() file text tags

the skin engine calls the tags for each conditional to check them since %ft
erases it's var if the file doesn't exist %?ft is likely only being called
to check existance of a file or line of a file

this patch allocates 2 bytes to satisify the conditional if the line exists

Change-Id: Ic74bf5fec9a5d9b6724692c49a0997bfa4cff48d

apps/gui/skin_engine/skin_parser.c

@@ -1380,7 +1380,13 @@ static int parse_filetext(struct skin_element *element,
         goto failure;
     }
 
+    if (element->is_conditional)
+    {
+        rd = 1; /* just alloc enough for the conditional to work*/
+    }
+
     buf[rd] = '\0';
+
     char * skinbuf = skin_buffer_alloc(rd+1);
 
     if (!skinbuf)

lib/skin_parser/skin_parser.c

@@ -932,6 +932,7 @@ static int skin_parse_conditional(struct skin_element* element, const char** doc
      * value */
     element->type = TAG;
     element->line = skin_line;
+    element->is_conditional = true;
 
     /* Parsing the tag first */
     if(!skin_parse_tag(element, &cursor))
@@ -1152,6 +1153,7 @@ static struct skin_element* skin_alloc_element()
     retval->params_count = 0;
     retval->children_count = 0;
     retval->data = INVALID_OFFSET;
+    retval->is_conditional = false;
 
     return retval;
 

lib/skin_parser/skin_parser.h

@@ -146,6 +146,7 @@ struct skin_element
     enum skin_element_type type;
     /* Number of elements in the params array */
     char params_count;
+    bool is_conditional;
 };
 
 enum skin_cb_returnvalue