Let installd dexopt OEM apps.

avc:  denied  { search } for  pid=118 comm="installd" name="/" dev="mmcblk0p12" ino=2 scontext=u:r:installd:s0 tcontext=u:object_r:oemfs:s0 tclass=dir

Bug: 13340779
Change-Id: Id42f45080ba2c736921691dadfdfa429cf006663

installd.te

@@ -16,6 +16,8 @@ allow installd data_file_type:dir { relabelfrom relabelto };
 allow installd data_file_type:{ file_class_set } { getattr unlink };
 allow installd apk_data_file:file r_file_perms;
 allow installd apk_tmp_file:file r_file_perms;
+allow installd oemfs:dir r_dir_perms;
+allow installd oemfs:file r_file_perms;
 allow installd system_file:file x_file_perms;
 allow installd cgroup:dir create_dir_perms;
 # Check validity of SELinux context before use.