Valid APK paths now include expanded storage.

Apps on expanded storage live at /mnt/expand/<uuid>/app/com.example,
so we need to relax one more directory level.

Bug: 19993667
Change-Id: I347ec7b92435ea69e632ed5d5fdfabe38ce0b56e
diff --git a/cmds/installd/installd.c b/cmds/installd/installd.c
index 5b71175..930ba2f 100644
--- a/cmds/installd/installd.c
+++ b/cmds/installd/installd.c
@@ -352,6 +352,11 @@
         return -1;
     }
 
+    // Get the android external app directory.
+    if (get_path_from_string(&android_mnt_expand_dir, "/mnt/expand") < 0) {
+        return -1;
+    }
+
     // Take note of the system and vendor directories.
     android_system_dirs.count = 4;