rework annex-ignore handling

Only one place need to filter the list of remotes for ignored remotes:
keyPossibilities. Make the full list available to everything else.

This allows getting rid of the special case handing for --from and --to
to make ignored remotes not be ignored with those options.

Remote/S3real.hs

@@ -67,7 +67,8 @@ gen' r u c cst =
 			removeKey = remove this,
 			hasKey = checkPresent this,
 			hasKeyCheap = False,
-			config = c
+			config = c,
+			repo = r
 		}
 
 s3Setup :: UUID -> RemoteConfig -> Annex RemoteConfig