efi_loader: error handling in efi_set_variable_common().

Fix unreachable code. Free memory on error.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 58f8fae..33df52e 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -981,7 +981,7 @@
 	if (append) {
 		old_data = malloc(old_size);
 		if (!old_data) {
-			return EFI_OUT_OF_RESOURCES;
+			ret = EFI_OUT_OF_RESOURCES;
 			goto err;
 		}
 		ret = EFI_CALL(efi_get_variable(variable_name, vendor,