Import webupd8 oracle java installer package
Fix config script.

This was previously using an undefined variable `dld` to construct the
filename it was looking for, which meant it would not use the
predownloaded file if it existed, and instead always attempt to download
the file from Oracle.

This appears to be a copy/paste error from the postinst script
Merge pull request #34 from alphagov/update_java_installer

Update java installer config script.