This is the second step towards getting rid of epochs/timestamps on config.chunks.

There are some functions that rely on the presence of epochs/timestamps on config.chunks to indentify a collection. This is fine for 4.4 but not for 5.0 since we plan to remove them. In 5.0 we should use the UUID instead (present on config.collections and config.chunks (since 5.0)).

Below you can find a list of functions that should be addressed:

1. ShardingCatalogManager::ensureChunkVersionIsGreaterThan
2. ShardingCatalogManager::clearJumboFlag
3. ShardingCatalogManager::commitChunkSplit
4. ShardingCatalogManager::commitChunkMerge
5. ShardingCatalogManager::commitChunkMigration
6. Catalog cache refreshes compare the epoch of config.collections and config.chunks to identify inconsistencies.