check_slow_queries_digest_result: threshold are floats

this program was comparing floats parsed from the report text and strings from
arguments passed on the command line, so basically it was not doing what was
intended.
13 jobs for fix/erp5-slow-queries-logs in 0 seconds
Status Job ID Name Coverage
  External
failed SlapOS.Eggs.UnitTest-Jerome.Python2

00:18:12

passed SlapOS.Eggs.UnitTest-Jerome.Python3

00:15:00

passed SlapOS.Eggs.UnitTest-Jerome.Python2

00:13:03

failed SlapOS.Eggs.UnitTest-Jerome.Python2

00:25:48

passed SlapOS.Eggs.UnitTest-Jerome.Python2

00:18:27

passed SlapOS.Eggs.UnitTest-Jerome.Python2

00:22:05

passed SlapOS.Eggs.UnitTest-Jerome.Python2

01:10:49

passed SlapOS.Eggs.UnitTest-Jerome.Python3

00:18:48

passed SlapOS.Eggs.UnitTest-Jerome.Python3

00:16:49

failed SlapOS.Eggs.UnitTest-Jerome.Python3

00:23:42

failed SlapOS.Eggs.UnitTest-Jerome.Python3

passed SlapOS.Eggs.UnitTest-Jerome.Python3

00:18:17

passed SlapOS.Eggs.UnitTest-Jerome.Python3

00:18:58