Addendum to r31096. Up basesmuma algorithm limits to 1M.

After discussion with Manju we decided to update these the process count
limits of the shared memory collectives to an arbitrarily large number.

cmr=v1.7.5:ticket=#4405
sbgp/basesmsocket: do not recalculate process locality

The necessary information is stored in the proc object. There is no need
to allgather the local process data to determine if another rank is on
the same socket.

cmr=v1.7.5:reviewer=manjugv
coll/ml: do not assert if a barrier algorithm is not available

It is usually not a good idea to assert when something is not implemented
or something goes wrong. Replace asserts with debug output and return.

cmr=v1.7.5:reviewer=manjugv
coll/ml: move error messages to verbose output

There are situations where coll/ml does not initialize properly. These will
eventually need to be fixed but in the meantime it is better to not always
print an error message because the collective framework can still fall back
on another collective module. This commit reduces the verbose output.

cmr=v1.7.5:reviewer=manjugv
coll/ml: fix valgrind warning about reading uninitialed value

This isn't causing any errors that I know about but it does fix an
annoying valgrind warning. Simple fix, no review required.

cmr=v1.7.5:reviewer=ompi-rm1.7
coll/ml: further improve the hierarchy discovery to handle the case where a
sbgp module fails to group any processes on any nodes.

cmr=v1.7.5:reviewer=manjugv
More corrections w.r.t. process groups

To accompany r31092 and r310924, also ensure to create a new process
group in the child right after the orted forks.  Add trivial configury
to ensure that we have setpgid, and only do the setpgid/getpgid if we
have setpgid.

Without this commit, killing the entire process group can do
unexpected things (e.g., kill the orted, mpirun, and even mpirun's
parent!).

cmr=v1.7.5:reviewer=rhc
coll/ml: really remove the asserts in the barrier setup

cmr=v1.7.5:reviewer=ompi-rm1.7