Revert "Nandroid: support selinux context inside tar archive"

This reverts commit 22f727bc48e4c272507619957241c95253d71e70.
Revert "format non vold extra storage to ext4 when no selinux context is defined"

This reverts commit 1795d57b5cecf74f4aae097383c1f85e21ffdf00.