Fixed gpg-keydescriptor

Makefile

@@ -32,7 +32,7 @@ $(KEYRING):
 
 	@# export all public keys to classic GPG keyring (APT cannot unterstand
 	@# new-style GPG keyboxes)
-	@$(GPG) --output "$@" --export repository@gruelag.de
+	@$(GPG) --output "$@" --export buero@gruelag.de
 
 	@# make exported keyring visible for dh_iservinstall3 (uses git ls-files)
 	@git add --intent-to-add --force "$@"; \