Fixes #3738: Move r29089 to v1.7 branch (A little cleanup - the)

---svn-pre-commit-ignore-below---

r29079 [[BR]]
Add support for autodetecting a MLNX HCA in the rmaps min distance feature. In this way, .ini files distributed with software stacks need not specify a particular HCA but instead may select the key word auto which will automatically select the discovered device. To use this feature, simply pass the keyword auto instead of a specific device name, --mca rmaps_base_dist_hca auto. If more than one card is installed, the mapper will inform the user of this and, at this point, the user will then need to specify which card via the normal route, e.g. --mca rmaps_base_dist_hca <dev_name>. This should be added to \ncmr=v1.7.4:reviewer=rhc:subject=Autodetect logic for min dist mapping

r29089 [[BR]]
A little cleanup - the base function to sort numa lists must return something or you get a warning about non-void function returning without value, so cleanup the return values. Ensure the mindist module actually checks for a return of "error" so it won't segfault, and have it emit a polite message when that happens.

cmr:v1.7.3:reviewer=jladd
Fixes #3717: Move r29010, r29065 to v1.7 branch

---svn-pre-commit-ignore-below---

r29010 [[BR]]
coll/ml: do not register variables in open and fix a bug in the coll/ml parser

cmr=v1.7.3:reviewer=pasha

r29065 [[BR]]
coll/ml: update the coll_ml_enable_fragmentation variable to support the
option to autodetect whether fragmentation should be enabled

cmr=v1.7.3:ticket=#3717