gcrypt, bup: Fix bug that prevented using these special remotes with encryption=pubkey.

I think both of these are all that's affected, but I went ahead and fixed
all the remotes that set their config to M.empty to instead store the
actual config. Who knows what will expect it to be actually present in
future, the Remote instance of getGpgEncParams came to..

Remote/Git.hs

@@ -120,7 +120,7 @@ gen r u c gc
 			, repairRepo = if Git.repoIsUrl r
 				then Nothing
 				else Just $ repairRemote r
-			, config = M.empty
+			, config = c
 			, localpath = localpathCalc r
 			, repo = r
 			, gitconfig = gc