index_col result is unexpected when usecols is used to skip a column
#### Code Sample, a copy-pastable example if possible

``` python
"""Example of Pandas bug."""
from pandas import read_csv
try:
    from StringIO import StringIO
except ImportError:
    from io import StringIO

csv = """A, B, C
1, 2, 3"""


def message(msg):
    """Print message."""
    msg_len = len(msg) + 2
    print('-' * msg_len + '\n {}\n'.format(msg) + '-' * msg_len)

message('raw file')
print(csv)


df = read_csv(StringIO(csv), names=['A', 'B', 'C'], skiprows=1, header=None,
              usecols=['B', 'C'])


message('expected result after skiping column A')
print(df)

df = read_csv(StringIO(csv), names=['A', 'B', 'C'], skiprows=1, header=None,
              usecols=['B', 'C'], index_col='B')

message('not expected result, if use index with column B')
print(df)
```
#### Expected Output

Current output:

```
----------
 raw file
----------
A, B, C
1, 2, 3
----------------------------------------
 expected result after skiping column A
----------------------------------------
   B  C
0  2  3
-------------------------------------------------
 not expected result, if use index with column B
-------------------------------------------------
   B
B   
3  2
```

Expected output:

```
----------
 raw file
----------
A, B, C
1, 2, 3
----------------------------------------
 expected result after skiping column A
----------------------------------------
   B  C
0  2  3
-------------------------------------------------
 not expected result, if use index with column B
-------------------------------------------------
   C
B   
2  3
```
#### output of `pd.show_versions()`
## INSTALLED VERSIONS

commit: None
python: 3.5.1.final.0
python-bits: 64
OS: Darwin
OS-release: 15.3.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: None

pandas: 0.17.1
nose: None
pip: 7.1.2
setuptools: 18.3.2
Cython: None
numpy: 1.10.1
scipy: 0.16.1
statsmodels: None
IPython: 4.0.1
sphinx: None
patsy: None
dateutil: 2.4.2
pytz: 2015.7
blosc: None
bottleneck: None
tables: None
numexpr: None
matplotlib: 1.5.0
openpyxl: 2.3.2
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: 4.4.1
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: None
pymysql: None
psycopg2: None
Jinja2: 2.8
