Update code to use pault.ag/go/sniff package (#5038)

* Update code to use pault.ag/go/sniff package

* Update go dependencies

vendor/github.com/mitchellh/go-ps/README.md

@@ -1,4 +1,4 @@
-# Process List Library for Go
+# Process List Library for Go [![GoDoc](https://godoc.org/github.com/mitchellh/go-ps?status.png)](https://godoc.org/github.com/mitchellh/go-ps)
 
 go-ps is a library for Go that implements OS-specific APIs to list and
 manipulate processes in a platform-safe way. The library can find and

vendor/github.com/mitchellh/go-ps/go.mod

@@ -0,0 +1,3 @@
+module github.com/mitchellh/go-ps
+
+go 1.13

vendor/github.com/mitchellh/go-ps/process_freebsd.go

@@ -1,4 +1,4 @@
-// +build freebsd,amd64
+// +build freebsd
 
 package ps
 

vendor/github.com/mitchellh/go-ps/process_unix.go

@@ -56,7 +56,7 @@ func processes() ([]Process, error) {
 
 	results := make([]Process, 0, 50)
 	for {
-		fis, err := d.Readdir(10)
+		names, err := d.Readdirnames(10)
 		if err == io.EOF {
 			break
 		}
@@ -64,14 +64,8 @@ func processes() ([]Process, error) {
 			return nil, err
 		}
 
-		for _, fi := range fis {
-			// We only care about directories, since all pids are dirs
-			if !fi.IsDir() {
-				continue
-			}
-
+		for _, name := range names {
 			// We only care if the name starts with a numeric
-			name := fi.Name()
 			if name[0] < '0' || name[0] > '9' {
 				continue
 			}