enableremote: Better handling of the unusual case where multiple special remotes...

enableremote: Better handling of the unusual case where multiple special remotes have been initialized with the same name

Before it would pick one at random, though preferring ones that were not
dead over dead ones.

Now, if one is dead and the other not, it will use the non-dead one. But if
both are not dead, or both dead, it will error out, suggesting the user
clarify what they want to enable.

Sponsored-by: Luke Shumaker on Patreon