Fixes bitcoin_cli

bitcoin_cli as a global variable in the main __init__.py was creating issues related to http.client.CannotSendRequest: Request-sent and connection re-usage. Define a new connection per request.

pisa/carrier.py

@@ -1,6 +1,6 @@
 from pisa.rpc_errors import *
-from pisa import bitcoin_cli
 from pisa.logger import Logger
+from pisa.tools import bitcoin_cli
 from pisa.utils.auth_proxy import JSONRPCException
 from pisa.errors import UNKNOWN_JSON_RPC_EXCEPTION
 
@@ -20,7 +20,7 @@ class Carrier:
     def send_transaction(self, rawtx, txid):
         try:
             logger.info("Pushing transaction to the network", txid=txid, rawtx=rawtx)
-            bitcoin_cli.sendrawtransaction(rawtx)
+            bitcoin_cli().sendrawtransaction(rawtx)
 
             receipt = Receipt(delivered=True)
 
@@ -70,7 +70,7 @@ class Carrier:
     @staticmethod
     def get_transaction(txid):
         try:
-            tx_info = bitcoin_cli.getrawtransaction(txid, 1)
+            tx_info = bitcoin_cli().getrawtransaction(txid, 1)
 
         except JSONRPCException as e:
             tx_info = None