Add -i to exec for compatibility reasons

No change to functionality

Issue: #606

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

Closes: #607
Approved by: rhatdan

cmd/podman/exec.go

@@ -19,6 +19,10 @@ var (
 			Name:  "privileged",
 			Usage: "Give the process extended Linux capabilities inside the container.  The default is false",
 		},
+		cli.BoolFlag{
+			Name:  "interactive, i",
+			Usage: "Not supported.  All exec commands are interactive by default.",
+		},
 		cli.BoolFlag{
 			Name:  "tty, t",
 			Usage: "Allocate a pseudo-TTY. The default is false",
@@ -43,6 +47,7 @@ var (
 		Action:                 execCmd,
 		ArgsUsage:              "CONTAINER-NAME",
 		SkipArgReorder:         true,
+		UseShortOptionHandling: true,
 	}
 )