userWidget: Actually respect the iconSize parameter

The iconSize parameter was only being respected if it was the
default icon fallback.

https://bugzilla.gnome.org/show_bug.cgi?id=706681

data/theme/gnome-shell.css

@@ -2244,8 +2244,6 @@ StScrollBar StButton#vhandle:active {
 .framed-user-icon {
     border: 2px solid #8b8b8b;
     border-radius: 5px;
-    width: 48pt;
-    height: 48pt;
     background-size: contain;
 }
 

js/ui/userWidget.js

@@ -29,7 +29,9 @@ const Avatar = new Lang.Class({
 
         this.actor = new St.Bin({ style_class: params.styleClass,
                                   track_hover: params.reactive,
-                                  reactive: params.reactive });
+                                  reactive: params.reactive,
+                                  width: this._iconSize,
+                                  height: this._iconSize });
     },
 
     setSensitive: function(sensitive) {