Revert "revert server API check to allow testing of pre-adjustment PRs"

This reverts commit a0f5ffd0a6e3b254773a268791f6f2f880913883
per https://github.com/openmicroscopy/openmicroscopy/pull/1653#issuecomment-27080752
have Python repository integration tests set hasher for import
Merge pull request #1725 from mtbc/trac-11202-negotiate-hasher

Restore server API check of hasher