[lint] Remove redundant exception variables

Use bare raise statement when reraising the exception that occured, and
remove unused exception variables.  Also remove a pointless exception
handler in discord.opus.

discord/voice_client.py

@@ -142,9 +142,9 @@ class VoiceClient:
 
         try:
             await asyncio.wait_for(self._handshake_complete.wait(), timeout=self.timeout, loop=self.loop)
-        except asyncio.TimeoutError as e:
+        except asyncio.TimeoutError:
             await self.terminate_handshake(remove=True)
-            raise e
+            raise
 
         log.info('Voice handshake complete. Endpoint found %s (IP: %s)', self.endpoint, self.endpoint_ip)
 
@@ -232,7 +232,7 @@ class VoiceClient:
 
                 if not reconnect:
                     await self.disconnect()
-                    raise e
+                    raise
 
                 retry = backoff.delay()
                 log.exception('Disconnected from voice... Reconnecting in %.2fs.', retry)