[BUG] DataFrame of Series objects unnecessarily sorts resulting column

[mroeschke]

Describe the bug
A clear and concise description of what the bug is.

Steps/Code to reproduce bug

In [27]: from cudf import *

In [28]:         series = [Series(i, index=["b", "a", "c"], name=str(i)) for i in range(3)]
    ...:         result = DataFrame(series)

In [29]: series
Out[29]: 
[b    0
 a    0
 c    0
 Name: 0, dtype: int64,
 b    1
 a    1
 c    1
 Name: 1, dtype: int64,
 b    2
 a    2
 c    2
 Name: 2, dtype: int64]

In [30]: result
Out[30]: 
   a  b  c
0  0  0  0
1  1  1  1
2  2  2  2

Expected behavior

In [30]: result
Out[30]: 
   b  a  c
0  0  0  0
1  1  1  1
2  2  2  2

Environment overview (please complete the following information)

• Environment location: Docker
• Method of cuDF install: conda