Change OSError to tty.error.

Signed-off-by: Soumendra Ganguly <soumendraganguly@gmail.com>

Author: 8vasu

Diff for: Lib/test/test_pty.py

@@ -96,7 +96,7 @@ def setUp(self):
                 self.stdin_dim = tty.tcgetwinsize(pty.STDIN_FILENO)
                 self.addCleanup(tty.tcsetwinsize, pty.STDIN_FILENO, \
                                 self.stdin_dim)
-            except OSError:
+            except tty.error:
                 pass
 
     def handle_sig(self, sig, frame):