The mechanism and value format of OHOS_DEPRECATED_DISTROS is identical
to OHOS_DEPRECATED_COLLECTIONS.

Deprecated distro configurations can be either completely removed or
replaced by another configuration. The format of OHOS_DEPRECATED_DISTROS
is a list of <DEPRECATED_DISTRO>:<REPLACEMENT_DISTRO>. When
<REPLACEMENT_DISTRO> is not provided, the distro was removed without a
replacement.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>