The blog-posts macro spaces parameter is converted twice, resulting in killed conversions

When a spaces parameter contains the name of a space that is not migrated at the root of the current wiki, the conversion of the blog-posts macro fails with the following exception:

Failed to convert the spaces parameter [Orphans.PBLAREA] of the blogpostlist macro.Killing the conversion.

This is because we try to convert a spaces parameter that has already been converted.

The fix is:

• not to convert the parameter a second time
• we don't actually need to kill the conversion and can let confluence reference through, this can be handled as a post migration fix