fix exception issue

jpush/common.py

@@ -91,6 +91,7 @@ class APIConnectionException(Exception):
 class APIRequestException(Exception):
     def __init__(self, value):
         self.value = value
+        super(Exception, self).__init__(value)
 
     def __str__(self):
         return repr(self.value)

jpush/core.py

@@ -36,7 +36,7 @@ class JPush(object):
         except requests.exceptions.ConnectTimeout:
             raise common.APIConnectionException("Connection to api.jpush.cn timed out.")
         except Exception:
-            raise common.APIConnectionException("Connection to api.jpush.cn error.")
+            raise common.APIRequestException("Connection to api.jpush.cn error.")
 
         logger.debug("Received %s response. Headers:\n\t%s\nBody:\n\t%s", response.status_code, '\n\t'.join(
                 '%s: %s' % (key, value) for (key, value) in response.headers.items()), response.content)