Optional — Promotion level of the ClearCase UCM baseline to be
downloaded at build-time.
If no promotion level is set (blank field), then the user will be presented
with all the ClearCase UCM baselines belonging to the ClearCase UCM
component defined above. If a promotion level is set, then, at build-time,
the user will be presented with only the ClearCase UCM baselines which have
been promoted to the specified level.