Revert "zygote: don't drop CAP_SYS_PTRACE from the bounding set."

This reverts commit 59972218f8c0d397fc50400a2b8b9be92ceeaf93.

Bug: http://b/34853272
Test: debuggerd -b `pidof system_server`
Change-Id: I440932210b6e84647c2848bab2e082a58338fb1e
1 file changed