Including current-series.rst in unreleased.rst results in the whole of
the current series release notes being rendered out twice. This causes
warnings to be thrown due to duplicated link labels between
current-series and unreleased. Under the new CI rulings warnings are
converted to errors resulting in release notes job failing.
Change-Id: Icae8efa962782beea6605acd48d2aff88eb6218c
fe10ce2ddb