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/Bup.hs

@@ -66,7 +66,8 @@ gen r u c = do
 			removeKey = remove,
 			hasKey = checkPresent r bupr',
 			hasKeyCheap = bupLocal buprepo,
-			config = c
+			config = c,
+			repo = r
 		}
 
 bupSetup :: UUID -> RemoteConfig -> Annex RemoteConfig