pyln-testing: pass timeout to BitcoinProxy

The bitcoin.rpc.DEFAULT_HTTP_TIMEOUT of 30 seconds may not be enough
time to generate a block when the test machine is under load. Pass
pyln.testing.utils.TIMEOUT to bitcoin.rpc.RawProxy to allow extra time:
currently 60 seconds by default or 180 seconds if SLOW_MACHINE is set.

Changelog-None

Author: whitslack

contrib/pyln-testing/pyln/testing/utils.py

@@ -366,16 +366,18 @@ class SimpleBitcoinProxy:
     throwaway connections. This is easier than to reach into the RPC
     library to close, reopen and reauth upon failure.
     """
-    def __init__(self, btc_conf_file, *args, **kwargs):
+    def __init__(self, btc_conf_file, timeout=TIMEOUT, *args, **kwargs):
         self.__btc_conf_file__ = btc_conf_file
+        self.__timeout__ = timeout
 
     def __getattr__(self, name):
         if name.startswith('__') and name.endswith('__'):
             # Python internal stuff
             raise AttributeError
 
         # Create a callable to do the actual call
-        proxy = BitcoinProxy(btc_conf_file=self.__btc_conf_file__)
+        proxy = BitcoinProxy(btc_conf_file=self.__btc_conf_file__,
+                             timeout=self.__timeout__)
 
         def f(*args):
             logging.debug("Calling {name} with arguments {args}".format(