#240 1.8 change: 'svn merge' will refuse to merge from an unrelated branch

[Pavel Lyalyakin]

http://subversion.apache.org/docs/release-notes/1.8.html#svn-merge-check-related

This enhacement should be helpful to avoid automatic reintegration merge to be performed at the wrong level of a related branch.

[C. Michael Pilato]

TODO:
1. Document this detail.
2. Give an example of what the failure case looks like.
3. Ensure that none of our other examples actually do this very thing and would in 1.8 fail.