Pandas 0.14 broke Python 2.6 support
Since today I've the following issue when importing Pandas on Python 2.6

```
2014-05-30 15:14:29.999 |   File "gnocchi/carbonara.py", line 22, in <module>
2014-05-30 15:14:29.999 |     import pandas
2014-05-30 15:14:29.999 |   File "/home/jenkins/workspace/gate-gnocchi-python26/.tox/py26/lib/python2.6/site-packages/pandas/__init__.py", line 45, in <module>
2014-05-30 15:14:30.000 |     from pandas.io.api import *
2014-05-30 15:14:30.000 |   File "/home/jenkins/workspace/gate-gnocchi-python26/.tox/py26/lib/python2.6/site-packages/pandas/io/api.py", line 7, in <module>
2014-05-30 15:14:30.000 |     from pandas.io.excel import ExcelFile, ExcelWriter, read_excel
2014-05-30 15:14:30.000 |   File "/home/jenkins/workspace/gate-gnocchi-python26/.tox/py26/lib/python2.6/site-packages/pandas/io/excel.py", line 626, in <module>
2014-05-30 15:14:30.000 |     .format(openpyxl_compat.start_ver, openpyxl_compat.stop_ver))
2014-05-30 15:14:30.000 | ValueError: zero length field name in format
```
