msi: Fix download of installer packages. Return errors from msi_download_file and copy_package_to_temp.

Found by Valgrind.

msi: Initialize type. If the value did not exist, type was uninitialized and passed to RegSetValueExW.

kernel32: Free the resource data if a matching resource exists and we choose not to overwrite the existing resource.

msi: Move MSITRANSFORM and MSISTREAM and associated methods to the dabatase implementation file as they are database objects/methods.

cryptnet: If the caller specifies the location of a CRL, check a cert's revocation status against it.

Trying to unlock a volume that isn't locked is questionable behaviour on the
side of the application, but not an internal error.

This is allowed behaviour.