sepolicy: selinux changes for persist due to mount point changes.

1- labeling /mnt/vendor/persist to mnt_vendor_file.
2- adding vendor_persit_type attrbute for persist
2- removing persist related rule for coredomains
3- Adding required policy to access persist

Change-Id: I8d769d4b06be44822f6d74e56f80be76a554bb9e