Merge #11882: Disable default fallbackfee on mainnet

3f592b8 [QA] add wallet-rbf test (Jonas Schnelli)
8222e05 Disable wallet fallbackfee by default on mainnet (Jonas Schnelli)

Pull request description:

  Removes the default fallback fee on mainnet (but keeps it on testnet/regtest).

  Transactions using the fallbackfee in case the fallback fee has not been set are getting rejected.

Tree-SHA512: e54d2594b7f954e640cc513a18b0bfbe189f15e15bdeed4fe02b7677f939bca1731fef781b073127ffd4ce08a595fb118259b8826cdaa077ff7d5ae9495810db

test/functional/test_runner.py

@@ -126,6 +126,7 @@ BASE_SCRIPTS= [
     'feature_cltv.py',
     'rpc_uptime.py',
     'wallet_resendwallettransactions.py',
+    'wallet_fallbackfee.py',
     'feature_minchainwork.py',
     'p2p_fingerprint.py',
     'feature_uacomment.py',