0021196: [CEA 456] Integration and merge modification for debian packages

0021196: [CEA 456] Integration and merge modification for debian packages

Remove unnecessary extern "C" instances and add one necessary one.
Background: One must not #include mpi.h from within an extern "C" block.
Both mpi.h and hdf5.h are C++-safe, and should be included directly without
extern "C".  For details, see:
http://www.open-mpi.org/community/lists/users/2007/12/4763.php