* Since we are adding a new function to `mca_coll_base_module_2_1_0_t`
we need to increase the version of the module structure to `2_2_0`.
* Add a comment just above the PREDEFINED_COMMUNICATOR_PAD describing
it's purpose and when it should change. To help future developers
trying to answer the question noted in the comment.
Signed-off-by: Joshua Hursey <jhursey@us.ibm.com>