BUG: Concat with inner join and empty DataFrame
Function `concat` with parameter `join='inner'` not return empty `DataFrame`:

    DF_empty = pd.DataFrame()
    DF_a = pd.DataFrame({'a': [1, 2]}, index=[0, 1])
    print (DF_empty)
    Empty DataFrame
    Columns: []
    Index: []
    
    print (DF_a)
       a
    0  1
    1  2
    
    print(pd.concat([DF_empty, DF_a], axis=1, join='inner'))
       a
    0  1
    1  2

But `merge` works nice:

    print (pd.merge(DF_empty, DF_a, left_index=True, right_index=True))
    Empty DataFrame
    Columns: [a]
    Index: []

[SO question](http://stackoverflow.com/questions/42084223/pandas-concat-inner-join-a-join-with-an-empty-dataframe-does-not-yield-an-empty)

---

    print (pd.show_versions())

<details>
    INSTALLED VERSIONS
    ------------------
    commit: None
    python: 3.5.1.final.0
    python-bits: 64
    OS: Windows
    OS-release: 7
    machine: AMD64
    processor: Intel64 Family 6 Model 60 Stepping 3, GenuineIntel
    byteorder: little
    LC_ALL: None
    LANG: sk_SK
    LOCALE: None.None
    
    pandas: 0.19.2
    nose: 1.3.7
    pip: 9.0.1
    setuptools: 20.3
    Cython: 0.23.4
    numpy: 1.11.0
    scipy: 0.17.0
    statsmodels: 0.6.1
    xarray: None
    IPython: 4.1.2
    sphinx: 1.3.1
    patsy: 0.4.0
    dateutil: 2.5.1
    pytz: 2016.2
    blosc: None
    bottleneck: 1.0.0
    tables: 3.2.2
    numexpr: 2.5.2
    matplotlib: 1.5.1
    openpyxl: 2.3.2
    xlrd: 0.9.4
    xlwt: 1.0.0
    xlsxwriter: 0.8.4
    lxml: 3.6.0
    bs4: 4.4.1
    html5lib: 0.999
    httplib2: None
    apiclient: None
    sqlalchemy: 1.0.12
    pymysql: None
    psycopg2: None
    jinja2: 2.8
    boto: 2.39.0
    pandas_datareader: 0.2.1
    None
<\details>