Fixes #4739: Move r32053 to v1.8 branch (If you don't specify all)

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r32053 [[BR]]
If you don't specify all the rank-file mapping for all procs, then you'll segfault - which is probably a bad idea. I can't see an easy workaround, so just error out for now and let's see if anyone really cares.

cmr=v1.8.2:reviewer=jsquyres


r32058 [[BR]]
Don't release the node_name field as it gets used in the slots parsing - will be released at newline detection