Histogram missing in Matplotlib 2.1.0 #9628

#!/usr/bin/env python3

import numpy as np
import matplotlib
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker
import collections

def plot_figure(distribution):
    percentile = [95, 99]
    percentile_color = 'yg'
    mean_color = 'c'
    bins = 100

    legend_handle = []
    legend_title = []

    fig, (ax0, ax1) = plt.subplots(2, sharex=True)
    fig.subplots_adjust(hspace=0)
    mu, sigma = 100, 15
    xs_downstream = mu + sigma*np.random.randn(10000)
    xs_upstream = mu + sigma*np.random.randn(10000)
    xmin = min(np.min(xs_downstream), np.min(xs_upstream))
    xmax = max(np.max(xs_downstream), np.max(xs_upstream))

    hist0 = ax0.hist(xs_downstream, bins=bins, range=(xmin, xmax), color='red', label='{} workload with Proxy'.format(distribution.capitalize()))
    handles, labels = ax0.get_legend_handles_labels()
    line = ax0.axvline(x=np.mean(xs_downstream), color=mean_color, linewidth=1)
    legend_title.append('Mean')
    legend_handle.append(line)

    for percent, color in zip(percentile, percentile_color):
        line = ax0.axvline(x=xs_downstream[int(percent / 100 * len(xs_downstream))], color=color, linewidth=1)
        legend_title.append('{}th percentile'.format(percent))
        legend_handle.append(line)

    ax0.set_yscale('log')
    legend_title += labels
    legend_handle += handles

    hist1 = ax1.hist(xs_upstream, bins=bins, range=(xmin, xmax), color='blue', label='{} workload without Proxy'.format(distribution.capitalize()))
    handles, labels = ax1.get_legend_handles_labels()
    legend_title += labels
    legend_handle += handles
    ax1.axvline(x=np.mean(xs_upstream), color=mean_color, linewidth=1)

    for percent, color in zip(percentile, percentile_color):
        ax1.axvline(x=xs_upstream[int(percent / 100 * len(xs_upstream))], color=color, linewidth=1)

    ax1.set_yscale('log')
    ax0.legend(legend_handle, legend_title)
    ax1.set_xlabel('latency (ms)')

    fig.savefig('latency-{}.pdf'.format(distribution))

def main():
    plot_figure('zipf')
    plot_figure('uniform')

if __name__ == '__main__':
    main()