fix pip install errors

This patch fixes the following errors when running `IHaskell console`:

* Jinja2 tarball, markupsafe not found

    ... ...
    Downloading/unpacking jinja2==2.7.1
      Real name of requirement jinja2 is Jinja2
    Saved /tmp/tmpThreadId12994/Jinja2-2.7.1.tar.gz
    ... ...
    Successfully downloaded jinja2 markupsafe
    Cleaning up...
    tar (child): jinja2-2.7.1.tar.gz: Cannot open: No such file or directory
    tar (child): Error is not recoverable: exiting now
    /bin/tar: Child returned status 2
    /bin/tar: Error is not recoverable: exiting now
    ... ...
    Couldn't find index page for 'markupsafe' (maybe misspelled?)
    Download error on http://pypi.python.org/simple/: timed out -- Some packages may not be found!
    No local packages or download links found for markupsafe
    error: Could not find suitable distribution for Requirement.parse('markupsafe')

* MarkupSafe already installed as a dependency of Jinja2

    Installed /admin/.ihaskell/ipython/lib/python2.7/site-packages/Jinja2-2.7.1-py2.7.egg
    Processing dependencies for Jinja2==2.7.1
    Searching for markupsafe
    Reading http://pypi.python.org/simple/markupsafe/
    Best match: MarkupSafe 0.18
    Downloading https://pypi.python.org/packages/source/M/MarkupSafe/MarkupSafe-0.18.tar.gz#md5=f8d252fd05371e51dec2fe9a36890687
    Processing MarkupSafe-0.18.tar.gz
    Running MarkupSafe-0.18/setup.py -q bdist_egg --dist-dir /tmp/easy_install-3rw7g1/MarkupSafe-0.18/egg-dist-tmp-XTNM3D
    Adding MarkupSafe 0.18 to easy-install.pth file
    
    Installed /admin/.ihaskell/ipython/lib/python2.7/site-packages/MarkupSafe-0.18-py2.7-linux-x86_64.egg
    Finished processing dependencies for Jinja2==2.7.1
    Installing dependency: MarkupSafe-0.18
    Downloading/unpacking MarkupSafe==0.18
      Downloading MarkupSafe-0.18.tar.gz
    The file /tmp/tmpThreadId16407/MarkupSafe-0.18.tar.gz exists. (i)gnore, (w)ipe, (b)ackup Exception:
    Traceback (most recent call last):
      File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 104, in main