edje: fix the image set bug.

edje: fix the image set bug.

Summary: Before using the parameter ep->param1.set, it should be set.

Test Plan:
 diff --git a/data/themes/edc/elm/button.edc b/data/themes/edc/elm/button.edc
 index 097ce85..34a2b98 100644
 --- a/data/themes/edc/elm/button.edc
 +++ b/data/themes/edc/elm/button.edc
@@ -3,6 +3,15 @@ group { name: "elm/button/base/default";
    alias: "elm/button/base/naviframe/back_btn/pager";
    images.image: "button_normal.png" COMP;
    images.image: "button_clicked.png" COMP;
+   images {
+      set {
+         name: "button_normal";
+         image {
+             image: "button_normal.png" COMP;
+             size: 0 0 9999 9999;
+         }
+      }
+   }
 #define ICON     1
 #define LABEL    2
 #define MASK     3
@@ -74,7 +83,7 @@ group { name: "elm/button/base/default";
    parts {
       image { "base"; nomouse;
          desc { "default";
-            image.normal: "button_normal.png";
+            image.normal: "button_normal";
             image.border: 4 4 3 5;
             image.middle: SOLID;
             rel1.offset: -1 0;

and print the value ep->param1.set about "base" part of "elm/button/base/default" group before it is used.
It has a NULL at first time.

Reviewers: raster, jinsol, herb, cedric

Subscribers: cedric

Differential Revision: https://phab.enlightenment.org/D1516

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>