meta-ohos: Change default DISTRO in zephyr's local.conf.sample

zephyr is no longer preferred, default DISTRO. Change it
to openharmony-zephyr.

Signed-off-by: Zbigniew Bodek <zbigniew.bodek@huawei.com>

flavours/zephyr/local.conf.sample

@@ -26,7 +26,7 @@ MACHINE ??= "qemu-x86"
 #
 # Default policy config
 #
-DISTRO = "zephyr"
+DISTRO = "openharmony-zephyr"
 
 #
 # Package Management configuration