George pointed out that r29991 wasn't quite right.  This patch is
added on top of r29991 and:

 * Consolidates the _debug variables in opal_datatype_internal.h and
   opal_convertor.h
 * Puts the DO_DEBUG macros back in the .c files, because they are
   slightly different from each other

Refs #4004
romio: pick "infinitely stale" fix from upstream

Some NFS scenarios can result in an infinite ESTALE return, which will
hang ROMIO.  This commit causes ROMIO to error out after a large number
of retries instead of spinning forever.

This is MPICH commit b250d338:

http://git.mpich.org/mpich.git/commit/b250d338e66667a8a1071a5f73a4151fd59f83b2

cmr=v1.7.5:reviewer=jsquyres