BUGFIX: If runtime cannot be found, error out

In the case where the runtime cannot be found, kpod should error
out.  This occurs in kpod ps when iterating through the containers
to get details.

Signed-off-by: baude <bbaude@redhat.com>

cmd/kpod/common.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"strings"
 
+	"fmt"
 	is "github.com/containers/image/storage"
 	"github.com/containers/storage"
 	"github.com/fatih/camelcase"
@@ -93,6 +94,10 @@ func getConfig(c *cli.Context) (*libkpod.Config, error) {
 	if c.GlobalIsSet("runtime") {
 		config.Runtime = c.GlobalString("runtime")
 	}
+	if _, err := os.Stat(config.Runtime); os.IsNotExist(err) {
+		// path to runtime does not exist
+		return config, fmt.Errorf("invalid --runtime value %q", err)
+	}
 	return config, nil
 }