lightningd: don't log JSON ids as debug, use log io.

They are cute, sure, but they do spam the logs.

@Suggested-by: @niftynei
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tests/test_misc.py

@@ -863,7 +863,7 @@ def test_malformed_rpc(node_factory):
 
 
 def test_cli(node_factory):
-    l1 = node_factory.get_node()
+    l1 = node_factory.get_node(options={'log-level': 'io'})
 
     out = subprocess.check_output(['cli/lightning-cli',
                                    '--network={}'.format(TEST_NETWORK),
@@ -874,7 +874,7 @@ def test_cli(node_factory):
     assert 'help [command]\n    List available commands, or give verbose help on one {command}' in out
 
     # Check JSON id is as expected
-    l1.daemon.wait_for_log("jsonrpc#[0-9]*: IN:id=cli:help#[0-9]*")
+    l1.daemon.wait_for_log(r"jsonrpc#[0-9]*: cli:help#[0-9]*\[IN\]")
 
     # Test JSON output.
     out = subprocess.check_output(['cli/lightning-cli',