LEAP2A import artefact fixer uses the wrong namespace

[Darryl Hamilton]

In trying to fix bug #675730, I found that the artefact_reference_quickcheck() and fix_artefact_reference() methods were using the wrong namespace variable/value.

The effect of this is those functions were looking for "http://terms.leapspecs.org/" as part of the text, where they should be looking for "leap2" instead.

A patch to fix this will be coming soon.