upped sleep time on 502 in getjson to 3 sec, trying to prevent cascading fail

etherdump/commands/common.py

@@ -58,7 +58,7 @@ def padpath2id (path):
     else:
         return p.decode("utf-8")
 
-def getjson (url, max_retry=3, retry_sleep_time=0.5):
+def getjson (url, max_retry=3, retry_sleep_time=3):
     ret = {}
     ret["_retries"] = 0
     while ret["_retries"] <= max_retry: