libdebuggerd: do a to-do.

Until 77fdb22c, logd started as
AID_ROOT and then dropped its privileges. Since then, there's been no
reason to use string comparisons rather than checking the uid.

Test: pkill -SEGV logd
Test: treehugger
Change-Id: Ia709f8f59cb0ab9abac7df84c96c701b5d0a83ea