thinca: change min_log_L logic

- allow min_log_L to be non-Null even if no ranking statistic has been
  supplied (causes all coincs to be discarded).
- this is needed to simply the "cold boot" feature being implemented in the
  gstlal pipeline.
12 jobs for thinca in 22 minutes and 10 seconds (queued for 1 second)
Status Job ID Name Coverage
  Level0
passed #65864
level0:lal

00:02:46

 
  Level1
passed #65865
level1:lalframe

00:01:30

passed #65866
level1:lalmetaio

00:01:09

passed #65867
level1:lalsimulation

00:02:30

passed #65868
level1:lalxml

00:01:09

 
  Level2
passed #65869
level2:lalburst

00:01:26

passed #65870
level2:lalinspiral

00:03:36

passed #65871
level2:lalpulsar

00:03:01

passed #65872
level2:lalstochastic

00:01:13

 
  Level3
passed #65873
level3:laldetchar

00:01:53

passed #65874
level3:lalinference

00:06:54

 
  Level4
passed #65875
level4:lalapps

00:06:22