Some functions in pandas are deprecated

[Masayuki Igawa]

I noticed that some functions in pandas are deprecated.
I think we should replace them with recommended functions.
----------
...../openstack-health/openstack_health/test_run_aggregator.py:79: FutureWarning: how in .resample() is deprecated
the new syntax is .resample(...).mean()
  base.resample_matrix[resample], how='mean')
...../openstack-health/openstack_health/test_run_aggregator.py:86: FutureWarning: pd.rolling_mean is deprecated for Series and will be removed in a future version, replace with
 Series.rolling(window=20,center=False).mean()
  numeric_df['avg_run_time'] = pd.rolling_mean(numeric_df['run_time'], 20)
...../openstack-health/openstack_health/test_run_aggregator.py:87: FutureWarning: pd.rolling_std is deprecated for Series and will be removed in a future version, replace with
 Series.rolling(window=20,center=False).std()
  numeric_df['stddev_run_time'] = pd.rolling_std(numeric_df['run_time'], 20)
----------

[Masayuki Igawa (igawa)]

More information:
http://pandas.pydata.org/pandas-docs/version/0.18.1/whatsnew.html?highlight=rolling_mean#window-functions-are-now-methods

[Masayuki Igawa (igawa)]

Series.rolling() function isn't in v0.17.x . So we need to upgrade the pandas version in requirements.txt.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/314874

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/314874
Committed: https://git.openstack.org/cgit/openstack/openstack-health/commit/?id=4db9a614711a2e52f9c827a9340e7ff7d1882751
Submitter: Jenkins
Branch: master

commit 4db9a614711a2e52f9c827a9340e7ff7d1882751
Author: Masayuki Igawa <email address hidden>
Date: Wed May 11 15:06:20 2016 +0900

    Fix pandas functions warnings

    This commit fixes pandas functions warnings. Some of pandas functions such as
    rolling_mean(), resample(how=xx) are deprecated from v0.18.0.

    Change-Id: I1465e50821af2aaa77d5458205469c4eec1dab58
    Closes-Bug: #1580447