Default to sha2 when sha2 is enabled

git-svn-id: svn://irodssvn.ucsd.edu/trunk@5635 ea137bd6-aa86-47b6-b90d-b101d9f19a90
Update irods2.sh (part of tinderbox) to run SHA256 file-hash once a
day; also fix a minor (non-fatal) bug when enabling SHA1 hash auth test.

The SHA256 file hash has not been passing the 'devtest' test suite
yet, but I thought I'd go ahead and put this in place as we complete
it.



git-svn-id: svn://irodssvn.ucsd.edu/trunk@5636 ea137bd6-aa86-47b6-b90d-b101d9f19a90