btl/vader: don't leak registration cache items

Make sure to cleanup the registation cache when removing an
endpoint. This leak only affects systems with XPMEM installed.

Since this is in code specific to XPMEM not sure who could review so
sending it directly to the RM.

cmr=v1.8.2:reviewer=ompi-rm1.8
bcol/basesmuma: fix leak in basesmuma code

Basesmuma was vallocing space for control data then mmapping over that
data. Nothing in the code suggests any need for mmapping a specific
address so I did the following to remove the leak:

 - Removed the valloc of the buffer space

 - ftruncate the mmaped file to ensure there is sufficient memory to
   allocate space for the control data.

Ideally this code should be using opal/shmem but that is a larger
change. Keeping it simple for now.

cmr=v1.8.2:reviewer=manjugv