Less scary warning when encountering shed XML during recursive tool load.

This might be entirely on the Galaxy side - but creating a issue here because it was encountered in the context of planemo machine.

Start by reproducing the recursive tool load through planemo machine with the shed XML that triggered the warning. Trace the recursive tool-loading entry point and determine whether the warning originates in planemo or Galaxy; done means the same input produces a clearer, less alarming warning.

Written by the indexing model from the issue text.