dms: tolerate ghostscript OCR reading "ERP5" as "ERPS"

this happens with new ghostscript, but this does not seem a critical
problem.
8 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

02:13:48

failed ERP5.PerformanceTest-Master

00:38:27

failed ERP5.UnitTest-Master

05:32:36

passed SlapOS.Eggs.UnitTest-Master.Python2

00:26:26

passed SlapOS.Eggs.UnitTest-Master.Python3

00:32:35

passed Wendelin.UnitTest-Master

01:03:13

failed ERP5.PerformanceTest-Master

00:35:55

passed SlapOS.Eggs.UnitTest-Master.Python3

00:30:27