prune: fix some UnicodeDecodeError on python3 with binary scripts

Some softwares have some binary executables in builout bin folder,
reading them as text can fail. In this case we can ignore them.
6 jobs for fix/prune-binary-scripts in 0 seconds
Status Job ID Name Coverage
  External
canceled SlapOS.Eggs.UnitTest-Jerome.Python2

49:29:28

passed SlapOS.Eggs.UnitTest-Jerome.Python3

00:22:58

passed SlapOS.Eggs.UnitTest-Jerome.Python2

03:01:10

failed SlapOS.Eggs.UnitTest-Jerome.Python2

01:06:28

passed SlapOS.Eggs.UnitTest-Jerome.Python3

02:36:44

passed SlapOS.Eggs.UnitTest-Jerome.Python3

01:13:17