Better error message when Sideset or Nodeset cannot be found

[permcody]

Bug Description

MOOSE gives an error message saying that certain "boundaries" do not exist in the mesh when in fact they do. The problem is that sometimes a specific type of boundary is missing (e.g. often a sideset doesn't exist but there's a nodeset with the given boundary ID). The error message is misleading and leaves the user confused as to what the problem is.

Steps to Reproduce

This error has arisen in several instances with Abaqus meshes:
https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/moose-users/kHlDjyzWa70/6JdRaUaXBwAJ

We should be able to create an Exodus mesh though that exhibits the same behavior by creating only a nodeset instead of a sideset that we attempt to use with an integrated boundary condition.

Impact

Minor: Generally this is isolated to bad mesh generation.