Always have an icon

The permission icon can be an external icon and thus might not exist.
So, ensure we always have an icon for the permissions UI.

Bug: 25602523
Change-Id: Ibdb1f296ff8c5f3664fe8056c8637844b580cce9
diff --git a/src/com/android/packageinstaller/permission/model/PermissionGroups.java b/src/com/android/packageinstaller/permission/model/PermissionGroups.java
index 59eba85..c496e89 100644
--- a/src/com/android/packageinstaller/permission/model/PermissionGroups.java
+++ b/src/com/android/packageinstaller/permission/model/PermissionGroups.java
@@ -212,11 +212,12 @@
         }
 
         private Drawable loadItemInfoIcon(PackageItemInfo itemInfo) {
-            final Drawable icon;
+            Drawable icon = null;
             if (itemInfo.icon > 0) {
                 icon = Utils.loadDrawable(getContext().getPackageManager(),
                         itemInfo.packageName, itemInfo.icon);
-            } else {
+            }
+            if (icon == null) {
                 icon = getContext().getDrawable(R.drawable.ic_perm_device_info);
             }
             return icon;