Audit_job and checksum_audit_logs updated to account for changes in Fedora 4.

    In ChecksumAuditLog we are saving the full URI of the resource that was audited. This URI could be http://xyz/content or http://xyz/content/fcr:versions/versionX. The MySQL table checksum_audit_logs remains unchanged. Later on we could update the table with a new column name if we want to.

    AuditJob was also refactored to receive the URI of the resource to audit. AuditJob does not searches for the datastream to audit since the URI gives a full path to it (as indicated in the previous paragraph.)
Merge pull request #727 from projecthydra/audit_fedora_4b

AuditJob and ChecksumAuditLog updated to account for changes in Fedora 4.