BLD: Import error during python 2.7  builds on travis
https://travis-ci.org/pydata/pandas/pull_requests

Recently the Python 2.7 builds on travis have been failing with the same error message. 

```
Traceback (most recent call last):
  File "setup.py", line 566, in <module>
    **setuptools_kwargs)
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/distutils/core.py", line 151, in setup
    dist.run_commands()
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/distutils/dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/Cython/Distutils/build_ext.py", line 163, in run
    _build_ext.build_ext.run(self)
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/distutils/command/build_ext.py", line 337, in run
    self.build_extensions()
  File "setup.py", line 305, in build_extensions
    build_ext.build_extensions(self)
  File "setup.py", line 88, in build_extensions
    numpy_incl = pkg_resources.resource_filename('numpy', 'core/include')
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/setuptools-18.1-py2.7.egg/pkg_resources/__init__.py", line 1160, in resource_filename
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/setuptools-18.1-py2.7.egg/pkg_resources/__init__.py", line 435, in get_provider
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/numpy/__init__.py", line 137, in <module>
    import add_newdocs
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/numpy/add_newdocs.py", line 9, in <module>
    from numpy.lib import add_newdoc
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/numpy/lib/__init__.py", line 13, in <module>
    from polynomial import *
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/numpy/lib/polynomial.py", line 17, in <module>
    from numpy.linalg import eigvals, lstsq, inv
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/numpy/linalg/__init__.py", line 48, in <module>
    from linalg import *
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/numpy/linalg/linalg.py", line 23, in <module>
    from numpy.linalg import lapack_lite
ImportError: libgfortran.so.1: cannot open shared object file: No such file or directory
```

```
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "pandas/__init__.py", line 16, in <module>
    "extensions first.".format(module))
ImportError: C extension: hashtable not built. If you want to import pandas from the source directory, you may need to run 'python setup.py build_ext --inplace' to build the C extensions first.
nosetests --exe -A slow and not network and not disabled pandas --doctest-tests --with-xunit --xunit-file=/tmp/nosetests.xml
E
======================================================================
ERROR: Failure: ImportError (C extension: hashtable not built. If you want to import pandas from the source directory, you may need to run 'python setup.py build_ext --inplace' to build the C extensions first.)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/nose/loader.py", line 418, in loadTestsFromName
    addr.filename, addr.module)
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/nose/importer.py", line 47, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/nose/importer.py", line 94, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/home/travis/build/pydata/pandas/pandas/__init__.py", line 16, in <module>
    "extensions first.".format(module))
ImportError: C extension: hashtable not built. If you want to import pandas from the source directory, you may need to run 'python setup.py build_ext --inplace' to build the C extensions first.
```
