[2855] Don't loop to check membership

src/lib/python/isc/server_common/bind10_server.py.in

@@ -149,8 +149,7 @@ class BIND10Server:
                     continue
                 else:
                     raise
-            for fileno in reads:
+            if cc_fileno in reads:
-                if fileno == cc_fileno:
                 # this shouldn't raise an exception (if it does, we'll
                 # propagate it)
                 self._mod_cc.check_command(True)