initremote: Prevent enabling encryption with exporttree=yes/importtree=yes

I do think this was a reversion, but I have not tracked back to what
version. While involving the remote config, it's not the same class of
problems that I kept having to chase down for a while after the remote
config parser reworking.

doc/bugs/initremote_with_export_and_import_allowed_with_encryption.mdwn

@@ -4,3 +4,5 @@ This should be rejected, but currently succeeds:
 
 There is code in adjustExportImportRemoteType, and I remember it used to
 work. --[[Joey]]
+
+> [[fixed|done]] --[[Joey]]