get_legend_handles_labels() for errorbar plot not working properly

Related to https://github.com/JuliaPy/PyPlot.jl/issues/401.

I'm simply trying to reverse the order of the legend entries of two errorbar plots.

Pure python (from within Julia):
```julia
py"""
import matplotlib.pyplot as plt
import numpy as np
plt.errorbar(np.random.rand(10), np.random.rand(10), np.random.rand(10), label='first', marker='o', linestyle="")
plt.errorbar(np.random.rand(10), np.random.rand(10), np.random.rand(10), label='second', marker='o', linestyle="")
h,l = plt.gca().get_legend_handles_labels()
plt.legend(reversed(h),reversed(l), frameon=True)
"""
```

Using PyPlot:
```julia
errorbar(rand(10), rand(10), rand(10), label="first", marker="o", linestyle="")
errorbar(rand(10), rand(10), rand(10), label="second", marker="o", linestyle="")
h,l = gca().get_legend_handles_labels()
legend(reverse(h),reverse(l), frameon=true)
```

Note that the handles are wrong (should be markers with error bars).

PyPlot + ugly fix:
```julia
errorbar(rand(10), rand(10), 0.1 .* rand(10), marker="o", linestyle="none", label="first")
errorbar(rand(10), rand(10), 0.1 .* rand(10), marker="o", linestyle="none", label="second")

py"""
import matplotlib.pyplot as plt
h, l = plt.gca().get_legend_handles_labels()
plt.legend(reversed(h), reversed(l), frameon=True)
"""
```

Presumably a PyObject conversion issue? In python, `h` is a container
```python
[,
]
```
In Julia I find
```julia
2-element Array{Tuple{PyObject,Tuple{PyObject,PyObject},Tuple{PyObject}},1}:
(PyObject , (PyObject , PyObject ), (PyObject ,))
(PyObject , (PyObject , PyObject ), (PyObject ,))
```

首先运行 issue 中的 Julia 示例，并检查 get_legend_handles_labels() 入口点及其 PyObject 转换。将返回的 errorbar 句柄与 Python 的 ErrorbarContainer 对象进行比较，然后验证反转这些句柄后图例中仍会保留误差条。

由索引模型根据 Issue 内容生成。