ValueError Exception during reset_index of timezone-aware data
``` python

import pandas as pd
import numpy as np
from datetime import datetime
import pytz

print "This is working:"
data = {23:np.nan, 24:-1949, 25:-1848, 26: np.nan}
date_without_timezone = datetime.now()
df = pd.DataFrame(data, index=[date_without_timezone,])
print df
print
print df.index
print
print df.stack()
print
print df.stack().reset_index() #Good (expected) result

print
print "--------------------"
print

print "This is NOT working:"
date_with_timezone = datetime.now(pytz.utc)
df_with_timezone = pd.DataFrame(data, index=[date_with_timezone,])
print df_with_timezone
print
print df_with_timezone.index
print
print df_with_timezone.stack()
print
print df_with_timezone.stack().reset_index() # EXCEPTION: ValueError: Length of values does not match length of index
```
## INSTALLED VERSIONS

commit: None
python: 2.7.5.final.0
python-bits: 32
OS: Windows
OS-release: 7
machine: AMD64
processor: Intel64 Family 6 Model 42 Stepping 7, GenuineIntel
byteorder: little
LC_ALL: None
LANG: PL

pandas: 0.14.1
nose: None
Cython: None
numpy: 1.8.1
scipy: None
statsmodels: None
IPython: 2.1.0
sphinx: None
patsy: None
scikits.timeseries: None
dateutil: 2.1
pytz: 2014.2
bottleneck: None
tables: None
numexpr: None
matplotlib: 1.3.1
openpyxl: 2.0.3
xlrd: 0.9.3
xlwt: 0.7.5
xlsxwriter: None
lxml: None
bs4: None
html5lib: None
httplib2: None
apiclient: None
rpy2: None
sqlalchemy: 0.9.4
pymysql: None
psycopg2: 2.5.3 (dt dec pq3 ext)
