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: I0d9cd14ecd0653c37c8aee3a6a4f4e076c92abee