wallet: Remove upgradewallet RPC

test/functional/wallet_multiwallet.py

@@ -183,9 +183,6 @@ class MultiWalletTest(BitcoinTestFramework):
         open(not_a_dir, 'a', encoding="utf8").close()
         self.nodes[0].assert_start_raises_init_error(['-walletdir=' + not_a_dir], 'Error: Specified -walletdir "' + not_a_dir + '" is not a directory')
 
-        self.log.info("Do not allow -upgradewallet with multiwallet")
-        self.nodes[0].assert_start_raises_init_error(['-upgradewallet'], "Error: Error parsing command line arguments: Invalid parameter -upgradewallet")
-
         # if wallets/ doesn't exist, datadir should be the default wallet dir
         wallet_dir2 = data_dir('walletdir')
         os.rename(wallet_dir(), wallet_dir2)