We should fail Podman with ExitCode 125 by default

$ ./bin/podman  --foo
$ echo $?
125
$ ./bin/podman  foo
Command "foo" not found.
See `podman --help`.
$ echo $?
1

After this change

$ ./bin/podman  foo
Command "foo" not found.
See `podman --help`.
$ echo $?
125

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

Closes: #1398
Approved by: vrothberg

cmd/podman/common.go

@@ -54,7 +54,7 @@ func usageErrorHandler(context *cli.Context, err error, _ bool) error {
 
 func commandNotFoundHandler(context *cli.Context, command string) {
 	fmt.Fprintf(os.Stderr, "Command %q not found.\nSee `%s --help`.\n", command, context.App.Name)
-	os.Exit(1)
+	os.Exit(exitCode)
 }
 
 // validateFlags searches for StringFlags or StringSlice flags that never had