NSW Prepdata persitification - Remove RDO warning

Hi everybody,

when the NSW prepdata is dumped to file, the code sometimes throws these warnings:

sTgcPrepDataContainerCnv                             181    13 WARNING Difference between cluster and rdo Identifier (-200) larger than what can be stored (127)
sTgcPrepDataContainerCnv                             181    13 WARNING Difference between cluster and rdo Identifier (-192) larger than what can be stored (127)
sTgcPrepDataContainerCnv                             181    13 WARNING Difference between cluster and rdo Identifier (-184) larger than what can be stored (127)

For one reason or another, the cluster holds the complete identifier of the strips used to form them. These identifiers are also written to disk. To save disk, they are compressed by assuming that the compact representation of each strip ID is very close to the representation of the central identifier. These warnings are a glimpse of the cases where the assumption breaks down and bogous numbers are dumped. Fortunately, the completely redundant strip numbers are saved as well which are not corrupted by compression. Plus, the RDO identifiers aren't really in use anywhere. To keep the story short, it's safe to simply remove the WARNING message. In a future scheme evolution of the EDM we will even remove this attribute.

Closes ATLASRECTS-7267 / ATLASRECTS-7158