Confusing errors when mismatching daml to package db

[samuel-williams-da]

If you end up in a situation where the daml you're using doesn't match the package-db, or dars you have already compiled, you can end up with confusing errors like

  <command line>: cannot satisfy --package "daml-stdlib-2.8.6(..[SNIP]..)"
      (use -v for more information)
  Failed to compile interface for data-dependency: daml-prim-041ddaabb3926f0b666d5e0a36bc1ae8dbf7191d2889afed5d1631af4172fa6b

This should be detectable and improved.