Remove the _debug prefixes for CMake debug builds (linux)

[brtnfld]

When CMake builds in debug mode, it creates library names appended with _debug; while this is common for Windows, it is not a common thing to do for Linux.

I propose leaving the same names for a release and debug builds for Linux/macOS.

[byrnHDF]

CMake allows one to change the postfix name, including setting it to nothing: set(CMAKE_DEBUG_POSTFIX) or -DCMAKE_DEBUG_POSTFIX=""

HDF5 uses that var setting for the names.