Zygote : Block SIGCHLD during fork. am: b1f1209d9a am: 35b8453338 am: 14bd75fa79 am: 50b0c3be57  -s ours am: e1e735bcb9
am: 072b70bae3

Change-Id: I15a813590f1e8aed95f2f7614971b40113b17521