openib/ugni: output verbose message when a BTL is ignored due to THREAD_MULTIPLE

usnic and portals4 already do this.

cmr=v1.8.2:reviewer=hjelmn
sctp: remove from trunk

At the developer meeting today, the question was raised as to whether
the SCTP BTL was maintained any more.  I emailed Alan Wagner to see if
he had any interest/resources to continue to maintain the SCTP BTL.
He indicated that he unfortunately had any resources to maintain it;
it would be fine to remove the SCTP BTL from the trunk.

So long, SCTP BTL... fare thee well...
Fix support for Cray alps

The alps ras and plm components were broken by recent changes in ORTE. This
commit resolves those issues.

Changes:

 - Define PMI2_SUCCESS if it isn't defined. This fixes a problem with Cray's
   PMI implementation which does not define (for some reason) PMI2_SUCCESS. We
   had previously just used PMI_SUCCESS.

 - Add missing definition and a typo in pml_alps_module.

 - launch_id is no longer available in the orte_node_t structure. Use the
   attribute lookup to get the value.

 - Do not use an O(n^2) sorting algorithm when putting alps nodes in order. Use
   opal_list_sort instead (O(nlogn)).
Per the developer conference, let's be a little nicer during MPI_Finalize and ease up on the cpu by inserting usleep into the loop over opal_progress while waiting for the RTE barrier to complete. This is a non-performant area of the code, and while most codes may call finalize at close-to-similar times, there are some that may choose to have one or more procs continue to perform some work prior to finalizing.

So save a little power while we are waiting.

cmr=v1.8.2:reviewer=jladd:subject=save power during finalize