QA: Fix race condition in wallet_encryption test

test/functional/wallet_encryption.py

@@ -49,7 +49,7 @@ class WalletEncryptionTest(BitcoinTestFramework):
         assert_equal(privkey, self.nodes[0].dumpprivkey(address))
 
         # Check that the timeout is right
-        time.sleep(2)
+        time.sleep(3)
         assert_raises_rpc_error(-13, "Please enter the wallet passphrase with walletpassphrase first", self.nodes[0].dumpprivkey, address)
 
         # Test wrong passphrase