don't print help message for usage errors

Don't print potentially verbose help messages in case of usage errors,
but print only the usage error followed by a pointer to the command's
help.  This aligns with Docker.

```
$ podman run -h
flag needs an argument: -h
See 'podman run --help'.
```

Signed-off-by: Valentin Rothberg <vrothberg@suse.com>

Closes: #1379
Approved by: rhatdan

1 files changed, 9 insertions, 0 deletions

diff --git a/cmd/podman/common.go b/cmd/podman/common.go
index 4ddfd5e0a..3d0f1159f 100644
--- a/cmd/podman/common.go
+++ b/cmd/podman/common.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"fmt"
 	"reflect"
 	"regexp"
 	"strings"
@@ -42,6 +43,14 @@ func shortID(id string) string {
 	return id
 }
 
+func usageErrorHandler(context *cli.Context, err error, _ bool) error {
+	cmd := context.App.Name
+	if len(context.Command.Name) > 0 {
+		cmd = cmd + " " + context.Command.Name
+	}
+	return fmt.Errorf("%s\nSee '%s --help'.", err, cmd)
+}
+
 // validateFlags searches for StringFlags or StringSlice flags that never had
 // a value set.  This commonly occurs when the CLI mistakenly takes the next
 // option and uses it as a value.