fix ready condition

Author: blink1073

pymongo/asynchronous/pool.py

@@ -1169,6 +1169,7 @@ async def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> A
 
         # Clear the backoff state.
         if self._backoff:
+            self._backoff = 0
             await self.ready()
 
         return conn

pymongo/synchronous/pool.py

@@ -1167,6 +1167,7 @@ def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> Connect
 
         # Clear the backoff state.
         if self._backoff:
+            self._backoff = 0
             self.ready()
 
         return conn