Move oci and shim to execution package

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

execution/shim/containerd-shim/process_pdeathsig.go

@@ -0,0 +1,15 @@
+// +build !solaris
+
+package main
+
+import (
+	"syscall"
+)
+
+// setPDeathSig sets the parent death signal to SIGKILL so that if the
+// shim dies the container process also dies.
+func setPDeathSig() *syscall.SysProcAttr {
+	return &syscall.SysProcAttr{
+		Pdeathsig: syscall.SIGKILL,
+	}
+}