controllers/default.py: log.info: Bad variable passed to record_id

Passing request.vars['samples_id'] as record_id caused some issues when several samples
were contained in the same sample set as the samples_id were separataed with commas, while
we expect a single ID.

See vdj#792
3 jobs for hotfix-s/error-on-save-analysis in 6 minutes and 59 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test Tools
passed #252979
test_tools

00:00:06

 
  Test Unit
passed #252980
web
test_server_unit

00:00:15

 
  Test Functional
passed #252981
docker x86_64
test_server_functional

00:06:37