Move some perms back to domain

libselinux stats selinuxfs, as does every process that links against
libselinux such as toolbox. grant:
   allow domain selinuxfs:filesystem getattr;

domain is already granted:
   allow domain self:dir r_dir_perms;
   allow domain self:lnk_file r_file_perms;
   allow domain self:{ fifo_file file } rw_file_perms;
To make these possible, also grant:
   allow domain proc:dir search;

Change-Id: Ife6cfa2124c9d61bf908ac89a8444676acdb4259