EX-4103 lamigo: rename some "check" functions

EX-4103 lamigo: rename some "check" functions

Despite the name of the feature, files are "hot" or "cold", while
pools are "fast" or "slow". Rename and reorganize some functions with
this in mind:

  lamigo_check_hot -> lamigo_sync_hot_files
  lamigo_new_job_for_hot -> lamigo_submit_sync
  lamigo_check_hot_one -> lamigo_sync_hot_to_fast
  lamigo_check_hot_on_cold -> lamigo_sync_hot_to_slow
  lamigo_get_hot -> lamigo_get_hot_files

Test-Parameters: trivial testlist=hot-pools
Change-Id: I2833c8828d73e50a72db8a19aae16d1400eccd66
Reviewed-on: https://review.whamcloud.com/45410
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alexandre Ioffe <aioffe@ddn.com>
Reviewed-by: John L. Hammond <jhammond@whamcloud.com>