Bug: AttributeError: 'error' object has no attribute 'errno'

This fixes an issue I am encountering where 'errno' is not an attribute of the 'select.error' class. This preserves the behavior should the errno attribute exist, but allows the old behavior (changed in commit efa531aa2364f2e4edad8ac646141bedf6b5b97e on 2013-12-30) to continue to function.

I got this issue when using pexpect3.1 on python2.7.3 and passing a SIGWINCH via signal after running interact

In short: I resize my window, pexpect causes program to crash

...
  File "/home/mprintz/temp/pexpect3/local/lib/python2.7/site-packages/pexpect/__init__.py", line 1690, in __select
    if err.errno == errno.EINTR:
AttributeError: 'error' object has no attribute 'errno'