Fix URL for Homebrew install in the hudson shell script (rebased onto dev_4_4)


This is the same as gh-1812 but rebased onto dev_4_4.

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This PR should fix the broken installation line in the OMERO-hombrew-install.sh script.

To test this PR, check the http://hudson.openmicroscopy.org.uk/job/OMERO-homebrew-stable/ turns green again.