edje_cc: don't warn when image attributes are missing in inherit_only group

Summary:
The inherit_only groups could be used for template of other groups.
So, even if it has image part, it dose not need to have image attributes.
@fix

Test Plan: N/A

Reviewers: cedric, conr2d, jpeg, raster

Reviewed By: raster

Differential Revision: https://phab.enlightenment.org/D4322

src/bin/edje/edje_cc_out.c

@@ -378,6 +378,9 @@ check_image_part_desc(Edje_Part_Collection *pc, Edje_Part *ep,
                       Edje_Part_Description_Image *epd, Eet_File *ef)
 {
    unsigned int i;
+   Edje_Part_Collection_Parser *pcp = (Edje_Part_Collection_Parser *)pc;
+
+   if (pcp->inherit_only) return;
 
    if (epd->image.id == -1 && epd->common.visible)
      WRN("Collection %s(%i): image attributes missing for "