debuggerd: fix missed use of ptrace(PTRACE_ATTACH). am: 8b6b654a5f am: fe59793375 am: 073f731836 am: 647ec18a9d  -s ours am: 364188b9d8
am: faa7e41a7f

Change-Id: Id3276ee167e8199917bb79a7d1cfdd8c409d7737