Allow dumpstate to communicate w/surfaceflinger through pipe.

Addresses the following denial:
Binder_3: type=1400 audit(0.0:76): avc: denied { read } for path="pipe:[232660]" dev="pipefs" ino=232660 scontext=u:r:dumpstate:s0 tcontext=u:r:surfaceflinger:s0 tclass=fifo_file permissive=0

Bug: 22333467
Change-Id: I0ea3462b02e0e93ca48e6c309f57c7c60f478e9b
1 file changed