check xkey type when we add the keystore, so that we cover all cases

lib/bitcoin.py

@@ -869,6 +869,9 @@ def deserialize_xpub(xkey):
 def deserialize_xprv(xkey):
     return deserialize_xkey(xkey, True)
 
+def xpub_type(x):
+    return deserialize_xpub(x)[0]
+
 
 def is_xpub(text):
     try: