used getRandomSubsetOfList(...) to reduce rows in MigrationTests
added blockedByBug 1105279 - rhn channel rhel-x86_64-server-scalefs-5
maps to a version 5.10 product cert - should be 5.1

added blockedByBug 1105331 - RHN channel to product cert mappings are
missing for rhel-x86_64-server-5-cf-tools-1-[beta-]debug channels

added blockedByBug - missing a few RHN Classic channel mappings to
product certs