How to run testr on window7

[QianBiao Ng]

1. clone from git
2. cd python-moganclient
3. tox -e py27

```
py27 runtests: commands[0] | python setup.py test --slowest --testr-args=
running test
'OS_STDOUT_CAPTURE' 不是内部或外部命令，也不是可运行的程序
或批处理文件。
running=OS_STDOUT_CAPTURE=${OS_STDOUT_CAPTURE:-1} \
OS_STDERR_CAPTURE=${OS_STDERR_CAPTURE:-1} \
OS_TEST_TIMEOUT=${OS_TEST_TIMEOUT:-60} \
${PYTHON:-python} -m subunit.run discover -t ./ .
======================================================================
FAIL: process-returncode
tags: worker-0
----------------------------------------------------------------------
returncode 1
Ran 1 tests
FAILED (id=6, failures=1)
error: testr failed (1)
ERROR: InvocationError: 'C:\\workspace\\python-nimbleclient\\.tox\\py27\\Scripts \\python.EXE setup.py test --slowest --testr-args='
___________________________________ summary ___________________________________
ERROR: py27: commands failed

```

[QianBiao Ng (woo.cubic)]

Let me translate the chinese part,

```
'OS_STDOUT_CAPTURE' 不是内部或外部命令，也不是可运行的程序或批处理文件。
```

-->

'OS_STDOUT_CAPTURE' is not a runnable program or bash command