updateClassifiers should not try to download failed artifact multiple times

[harrah]

An example of the output for a run in my multi-module project:

[ijuma@localhost]~% cat sbt-output| grep "NOT FOUND" | grep xerces
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (359ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (359ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (122ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (122ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (121ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (121ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (123ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (123ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (121ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (121ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (122ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (122ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (374ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (374ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (130ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (130ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (129ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (129ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (132ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (132ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (130ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (130ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (129ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (129ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (130ms)
[warn] [NOT FOUND ] xerces#xercesImpl;2.9.1!xercesImpl.jar (130ms)

[harrah]

IMPORTANT This project has moved to https://github.com/sbt/sbt. This issue still exists to avoid dead links, but GitHub limitations prevent the original issue from being correctly preserved here. Please see sbt/sbt#46 for the full issue and to comment.