Stokhos: Remove Build Warnings

Created by: ZUUL42

@trilinos/stokhos

Expectations

Stokhos builds should not emit any warnings that will be promoted to errors once Werror is set in the GCC 7.2.0 automated build.

Current Behavior

Currently Stokhos has a number of warnings that need to be handled before we can set Werror for all packages. A recent test build was performed with -Werror set for Stokhos. The CDash report can be found here.

Motivation and Context

Issue #3178 is working toward turning Warnings as Errors on for all packages.