[#330] morph: Fix linter issue

Revive became smarter after go 1.20.4 upgrade.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

cmd/frostfs-adm/internal/modules/morph/initialize_deploy.go

@@ -402,9 +402,8 @@ func (c *initializeContext) readContracts(names []string) error {
 		var r io.ReadCloser
 		if c.ContractPath == "" {
 			return errors.New("contracts flag is missing")
-		} else {
-			r, err = os.Open(c.ContractPath)
 		}
+		r, err = os.Open(c.ContractPath)
 		if err != nil {
 			return fmt.Errorf("can't open contracts archive: %w", err)
 		}