Bug: unclear that tag IDs are expected

[jamoore]

bin/omero tag createset: error: unrecognized arguments: JoshSet
jamoore@blue:/tmp/OMERO.server-5.0.0-beta2-RC3-ice35-b9$ bin/omero tag createset --name JoshSet --tag A B C D
Please enter a description for this tag set: Don't make me enter a description! Oh, man!
Traceback (most recent call last):
  File "bin/omero", line 125, in <module>
    rv = omero.cli.argv()
  File "/tmp/OMERO.server-5.0.0-beta2-RC3-ice35-b9/lib/python/omero/cli.py", line 1195, in argv
    cli.invoke(args[1:])
  File "/tmp/OMERO.server-5.0.0-beta2-RC3-ice35-b9/lib/python/omero/cli.py", line 745, in invoke
    stop = self.onecmd(line, previous_args)
  File "/tmp/OMERO.server-5.0.0-beta2-RC3-ice35-b9/lib/python/omero/cli.py", line 814, in onecmd
    self.execute(line, previous_args)
  File "/tmp/OMERO.server-5.0.0-beta2-RC3-ice35-b9/lib/python/omero/cli.py", line 894, in execute
    args.func(args)
  File "/tmp/OMERO.server-5.0.0-beta2-RC3-ice35-b9/lib/python/omero/plugins/tag.py", line 499, in createset
    link.child = TagAnnotationI(rlong(long(t)), False)
ValueError: invalid literal for long() with base 10: 'A'
jamoore@blue:/tmp/OMERO.server-5.0.0-beta2-RC3-ice35-b9$ 

[jamoore]

Minor rfe: requiring a description is a bit frustrating.

[sbesson]

See ​https://github.com/openmicroscopy/openmicroscopy/pull/1903.
Corresponding tests are under test/unit/clitest as the command should now fail-fast with wrong input type.

As for the RFE, waiting to have Sam's opinion on it as he is the one who wrote it in the first place and we do not want to break any existing usage.