White cuda/9.2 + gcc/7.2 warnings triggering errors

[ndellingwood]

In the White Jenkins jobs (e.g. Kokkos_develop_white_cuda_92_gcc_720_kepler) there are warnings triggering failures:

03:50:20 /home/jenkins/white/workspace/Kokkos_develop_white_cuda_92_gcc_720_kepler/kokkos/core/src/Cuda/Kokkos_Cuda_Parallel.hpp:1248:32: error: enum constant in boolean context [-Werror=int-in-bool-context]
03:50:20    enum { UseShflReduction = (true && ValueTraits::StaticValueSize) };

This is occurring after allowing -Werror for the Cuda builds in the test_all_sandia script in #1817

[ndellingwood]

Fixed in PR #1837; other gcc/7.2 warning fixes scattered in different PRs.