Fix exception in _parse_srv_result_nt() (on Windows)

Sometimes 'result' parameter is byte[] which causes exception:
TypeError: 'str' does not support the buffer interface

src/common/resolver.py

@@ -198,7 +198,7 @@ class NSLookupResolver(CommonResolver):
         if not result:
             return []
         hosts = []
-        lines = result.replace('\r', '').split('\n')
+        lines = str(result).replace('\r', '').split('\n')
         current_host = None
         for line in lines:
             line = line.lstrip()