bpo-18035: telnetlib: select.error doesn't have an errno attribute (#5044)

select.error doesn't have an errno attribute so access the errno by
indexing instead.
diff --git a/Lib/telnetlib.py b/Lib/telnetlib.py
index 2eaa8e3..d0246c0 100644
--- a/Lib/telnetlib.py
+++ b/Lib/telnetlib.py
@@ -317,7 +317,7 @@
                     ready = poller.poll(None if timeout is None
                                         else 1000 * call_timeout)
                 except select.error as e:
-                    if e.errno == errno.EINTR:
+                    if e[0] == errno.EINTR:
                         if timeout is not None:
                             elapsed = time() - time_start
                             call_timeout = timeout-elapsed
@@ -688,7 +688,7 @@
                     ready = poller.poll(None if timeout is None
                                         else 1000 * call_timeout)
                 except select.error as e:
-                    if e.errno == errno.EINTR:
+                    if e[0] == errno.EINTR:
                         if timeout is not None:
                             elapsed = time() - time_start
                             call_timeout = timeout-elapsed