Fixes #3976: Move r29911 to v1.7 branch (add mlnx packages autodetect logic)

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

r29911 [[BR]]
add mlnx packages autodetect logic
cmr=v1.7.4:reviewer=ompi-gk1.7
Fixes #3975: Move r29910 to v1.7 branch (Update platform files)

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

r29910 [[BR]]
Update platform files

cmr=v1.7.4:reviewer=ompi-gk1.7


r29913 [[BR]]
Seems to work either way, but add semi-colon for correctness