Bug report

When acorr() is given a label, it uses it for two different lines, resulting in two near-identical entries in the legend.

Code for reproduction

#!/usr/bin/env python
import numpy as np
import matplotlib.pyplot as plt

x = np.random.normal(0, 10, 1000)

plt.figure()
plt.acorr(x, label='x')
plt.legend(loc='upper right')
plt.show()

Actual outcome

Expected outcome

Matplotlib version

• Matplotlib version: 2.0.0