DFU file query is NO LONGER completely case insensitive

Performing a DFU query will fail if the cluster prefix portion of the file name doesn't match exactly (case must now match)

This was not the case as recently as 4.2.8RC3

Note: There is somewhat of a work-around provided by Kevin which is to add a wildcard at the start of the string.
However, this is a regression non the less that should be resolved.