Allow dumpstate and shell to list services.

Addresses the following denials:
avc:  denied  { list } for service=NULL scontext=u:r:shell:s0 tcontext=u:r:servicemanager:s0 tclass=service_manager
avc:  denied  { list } for service=NULL scontext=u:r:dumpstate:s0 tcontext=u:r:servicemanager:s0 tclass=service_manager

Bug: 18864737
Change-Id: I72bd2cd9663f1df9410c2139411038fa997bf1b4