dumpstate: allow pstore access

Dumpstate reads from /sys/fs/pstore/console-ramoops when generating
a bug report. Allow it.

Addresses the following denials:
  <12>[ 2187.362750] type=1400 audit(1402346777.139:9): avc: denied { search } for pid=4155 comm="dumpstate" name="/" dev="pstore" ino=9954 scontext=u:r:dumpstate:s0 tcontext=u:object_r:pstorefs:s0 tclass=dir permissive=1
  <12>[ 2187.363025] type=1400 audit(1402346777.139:10): avc: denied { getattr } for pid=4155 comm="dumpstate" path="/sys/fs/pstore/console-ramoops" dev="pstore" ino=9955 scontext=u:r:dumpstate:s0 tcontext=u:object_r:pstorefs:s0 tclass=file permissive=1
  <12>[ 2187.363185] type=1400 audit(1402346777.139:11): avc: denied { read } for pid=4155 comm="dumpstate" name="console-ramoops" dev="pstore" ino=9955 scontext=u:r:dumpstate:s0 tcontext=u:object_r:pstorefs:s0 tclass=file permissive=1
  <12>[ 2187.363321] type=1400 audit(1402346777.139:12): avc: denied { open } for pid=4155 comm="dumpstate" path="/sys/fs/pstore/console-ramoops" dev="pstore" ino=9955 scontext=u:r:dumpstate:s0 tcontext=u:object_r:pstorefs:s0 tclass=file permissive=1

Change-Id: Ia20b7a03ed8e0c61b023eea93415a50af82e1bbf