[CentOS] C7 and mdadm - apparently SOLVED

Looking around on the Web, what I just tried was to stop the RAID, then do
an --assemble --scan, and *that* found everything, put the raid together,
and appears to be rebuilding using the new drive.

*phew*

I do find it interesting that scan works, but explicitly assembling
apparently remembers the drive that died, and wouldn't even look at it.

     mark