sepolicy: allow charger to read /sys/fs/pstore/console-ramoops

Addresses the denial in charger mode:
[   17.993733] type=1400 audit(1405412231.119:4): avc:  denied  { search } for  pid=123 comm="charger" name="/" dev="pstore" ino=10287 scontext=u:r:healthd:s0 tcontext=u:object_r:pstorefs:s0 tclass=dir permissive=0

Change-Id: I95e65753a99aa61ef86b8eebb7083b3d450e6b7b