In the Task `PorpelSQLDiffTask` the `disableIdentifierQuoting` build property was not handled.

Before this PR, the task 'sql-diff' did always include quotes around identifier, no matter if you set `disableIdentifierQuoting` to `true` or not.
Merge pull request #589 from MArcJ/fix-sqldiff-quotes

In the Task `PorpelSQLDiffTask` the `disableIdentifierQuoting` build property was not handled