Revert "coll/basic: fix segmentation fault in neighborhood collectives if the degree"

This reverts commit 9c788ff9400960823637dc0eebb3a8640414fa05.
coll/basic: fix segmentation fault in neighborhood collectives if the degree
of the topology is higher than the communicator size

It is possible to have a topology degree higher than the size of the communicator.
For example, a periodic cartesian communicator on MPI_COMM_SELF. This will leave
the neighborhood collectives with a request buffer that is too small.

This commits introduces a semantic change :
from now, c_topo must be set before invoking coll_select
* comment on communicator creation in mca_topo_base_dist_graph_create(...)
* use accesors to retrieve topo info
Silence some warnings and remove debug output
Merge pull request #227 from ggouaillardet/rfc/coll_basic_neighbor

RFC/coll basic neighbor
Make sure initialization happens
Missed a removal from previous commit
Doh - if we can't output an entire block, then we need to adjust the number of bytes remaining to be output or else we will output duplicate bytes when next we are able to write.
enable ugni btl to work without disable-dlopen

There were mistakes in the Makefiles for the ugni btl and
mca/common/ugni that prevented the ugni btl from being
used unless one happened to set the --disable-dlopen option
on the config line.

This commit fixes this problem.
topo/base: fix uninitialized variable

this commit fixes a bug introduced by commit open-mpi/ompi@e7c59e3adbcec5693c5df0057de6c66ed2b80817
btl/vader: use FRAG_ALLOC_USER when single_copy_mechanism is VADER_NONE
OSHMEM: sshmem verbs: fix shared_mr detection

It seems that 5ce2f1006762ef908b2960df5b93dc7532f8e448
changed default flag values but it did not modify detection code.
NEWS: sync with 1.8.4 bullets
NEWS: whitespace cleanup; no content changes
OpenMPI.3in: remove trailing blank lines; no content changes
another fix for --enable-dlopen for ugni btl

missed a change to create libmca_common_ugni.la
file correctly.
Support physical processor ids in rankfile
Restore handling of physical processors in rankfiles. Note that the prior implementation was likely incorrect as it falsely assumed that physical core indices were unique, which isn't always true. Stipulate that physical rankfiles can only include PU numbers, and bind the result to the core that contains that physical PU. Update the mpirun man page to cover the new use-case.
pmix: correctly split pmi messages

Thanks to @elenash for all the reviews
Merge pull request #245 from ggouaillardet/poc/pmi_slurm

pmix: correctly split pmi messages