integration: add _test suffix to files

Some files in integration did not have _test, resulting in lots of
complains when running golangci-lint with --tests=false.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

integration/procutils_linux_test.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+// cmdLifecycleToParentIfPossible is a thin wrapper around prctl(PR_SET_PDEATHSIG)
+// on Linux.
+func cmdLifecycleToParentIfPossible(c *exec.Cmd) {
+	c.SysProcAttr = &syscall.SysProcAttr{
+		Pdeathsig: syscall.SIGTERM,
+	}
+}