read_msgpack returns a List of length Zero
I have a very large Data Frame that takes 10.7 GB when serialized with "to_csv", but it takes 6.7 GB when using "to_msgpack". When reading the serialized file with "read_msgpack", I get a type List of length Zero.

The same IO process on 200 MB Data Frame works perfectly, i.e. a Data Frame is returned by the function "read_msgpack".
#### Code Sample, a copy-pastable example if possible

type(df) -> pd.DataFrame
len(df) -> 39227674
df.to_msgpack('foo.msg')
df2 = pd.read_msgpack('foo.msg')
type(df2) -> List
len(df2) -> 0
#### Expected Output

type(df2) -> pd.DataFrame
len(df2) -> 39227674
#### output of `pd.show_versions()`
## INSTALLED VERSIONS

commit: None
python: 2.7.3.final.0
python-bits: 64
OS: Linux
OS-release: 3.2.0-49-virtual
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.18.1
nose: 1.1.2
pip: 8.1.2
setuptools: 1.4
Cython: 0.23.4
numpy: 1.11.0
scipy: 0.17.0
statsmodels: None
xarray: None
IPython: 4.0.0
sphinx: None
patsy: None
