python3.2: test_html  ImportError: html5lib not found please install it
Now (d070a1f) that #4265 fixed, all the test_html tests fail similarly

```
======================================================================
ERROR: test_bad_url_protocol (pandas.io.tests.test_html.TestReadHtmlBase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/yoh/deb/gits/pkg-exppsy/build-area/pandas-0.12.0~rc1+git101-gd070a1f/debian/tmp/usr/lib/python3/dist-packages/pandas/io/tests/test_html.py", line 290, in test_bad_url_protocol
    '.*Water.*')
  File "/usr/lib/python3.2/unittest/case.py", line 557, in assertRaises
    callableObj(*args, **kwargs)
  File "/home/yoh/deb/gits/pkg-exppsy/build-area/pandas-0.12.0~rc1+git101-gd070a1f/debian/tmp/usr/lib/python3/dist-packages/pandas/io/tests/test_html.py", line 91, in run_read_html
    return read_html(*args, **kwargs)
  File "/home/yoh/deb/gits/pkg-exppsy/build-area/pandas-0.12.0~rc1+git101-gd070a1f/debian/tmp/usr/lib/python3/dist-packages/pandas/io/html.py", line 906, in read_html
    attrs)
  File "/home/yoh/deb/gits/pkg-exppsy/build-area/pandas-0.12.0~rc1+git101-gd070a1f/debian/tmp/usr/lib/python3/dist-packages/pandas/io/html.py", line 765, in _parse
    parser = _parser_dispatch(flav)
  File "/home/yoh/deb/gits/pkg-exppsy/build-area/pandas-0.12.0~rc1+git101-gd070a1f/debian/tmp/usr/lib/python3/dist-packages/pandas/io/html.py", line 719, in _parser_dispatch
    raise ImportError("html5lib not found please install it")
ImportError: html5lib not found please install it
```
