Dumpstate: cleanup denial logspam

Dumpstate lists all services and then enumerates over them. Suppress
"find" denials for services which dumpstate is neverallowed access
to.

Dumpstate includes the kernel command line in bug reports. Grant access
to /proc/cmdline.

Test: build. Run adb bugreport.
Change-Id: I89b546c728a034638f9257c6cf93366d99a10762