fixed message commands in CMakeLists.txt, and ncdump dependency problems for tst_nccopy4 in CMake build

[edwardhartnett]

Fixes #2982
Fixes #2395

[WardF]

An interesting thing to note about the DEPENDS directive in cmake is that it specifies the order in which tests are run. It does not enforce test X completing before running test Y, even if X is set as a dependency on Y. There is a mechanism around this that I started poking at before leaving for PTO last week, and I will get back to it this week.