libMesh/libmesh — pull request #280 by roystgnr (2014-06-27 19:42:25+00:00)
Title: Handle key collisions when stitching meshes

This triggered for me with a 16-bit dof_id_type buildbot test, but
there's no reason it couldn't happen with a larger id type and much
worse luck.

This isn't the only outstanding bug with that configuration, but it seems to be an independent and relatively simple problem so let's see what MooseBuild thinks of the fix.