Fixes #4081: Move r30214 to v1.7 branch (ob1 does not check the)

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r30214 [[BR]]
ob1 does not check the return code of mpool_register. This can cause the
ob1 dummy registration to actually be used when using udreg. Fix this by
always setting reg to NULL when mpool/udreg's register function fails.

cmr=v1.7.4:reviewer=rhc
Fixes #4082: Move r30215 to v1.7 branch (Update Mac support for 10.8)

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r30215 [[BR]]
Update Mac support for 10.8 and 10.9 - need to review about earlier versions

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


r30219 [[BR]]
Update README for interconnects

Refs #4082
Sigh - remove stale references to udapl and quadrics