remove redundant argument check from cli.Parse

This is also done in the Executor. Unfortunately, doing this *here* causes us to
block until we get an argument from stdin, even if we're handling a help call.

cli/parse.go

@@ -49,10 +49,6 @@ func Parse(ctx context.Context, input []string, stdin *os.File, root *cmds.Comma
 		return req, err
 	}
 
-	if err := req.Command.CheckArguments(req); err != nil {
-		return req, err
-	}
-
 	// if no encoding was specified by user, default to plaintext encoding
 	// (if command doesn't support plaintext, use JSON instead)
 	if enc := req.Options[cmds.EncLong]; enc == "" {

cli/parse_test.go

@@ -480,6 +480,9 @@ func TestBodyArgs(t *testing.T) {
 		}
 
 		req, err := Parse(context.Background(), tc.cmd, tc.f, rootCmd)
+		if err == nil {
+			err = req.Command.CheckArguments(req)
+		}
 		if !errEq(err, tc.parseErr) {
 			t.Fatalf("parsing request for cmd %q: expected error %q, got %q", tc.cmd, tc.parseErr, err)
 		}