Error message more explicit

[atarkowska]

I think error message could be more explicit, to point to narrow down by flag. Even better, giving example would be very clear what is wrong.

Probably when release is out default ICE version would be good idea too.

(omego) $ omego download py --branch OMERO-DEV-merge-build
2016-04-28 10:24:05,893 [omego.artifa] ERROR Found 2 matching matrix build runs: ['https://ci.openmicroscopy.org/job/OMERO-DEV-merge-build/ICE=3.5,jdk=8_LATEST,label=octopus/295/', 'https://ci.openmicroscopy.org/job/OMERO-DEV-merge-build/ICE=3.6,jdk=8_LATEST,label=octopus/295/']
ERROR: Expected one matching run, found 2

see #85

[manics]

If we do have a "default" ice version for CI I'd prefer if this could be indicated somehow on the CI side, otherwise omego requires code changes everytime there's a new version.

[manics]

Also that's a generic error message for matrix builds with multiple versions of anything, it's not just ice that could cause it.