Fix removal of old versions in setuptools
Manually remove "Only in" line
Trac #17268: Fix removal of old versions in setuptools

The setuptools patch
`build/pkgs/setuptools/patches/easy_install_lock.patch` from #13201
breaks the removal of old versions of packages.

This has the following effect in Sage:
the wrong version of sagenb is used. Even after an explicit `./sage -f
sagenb` installing `sagenb-0.11.0`, Sage still thinks I want to use an
older version.

Looking at `local/lib/python2.7/site-packages/easy-install.pth` shows
{{{
[...]
./Flask_OpenID-1.2.4-py2.7.egg
./sagenb-0.10.7.2-py2.7.egg
./zope.interface-4.0.5-py2.7-linux-x86_64.egg
./sagenb-0.10.8.2-py2.7.egg
./sagenb-0.11.0-py2.7.egg
./itsdangerous-0.23-py2.7.egg
[...]
}}}

This leads to the following doctest failure:
{{{
$ ./sage -tp --long --sagenb
too many failed tests, not using stored timings
Running doctests with ID 2014-10-31-14-01-49-cac56b83.
Doctesting the Sage notebook.
Sorting sources by runtime so that slower doctests are run first....
Doctesting 51 files using 4 threads.
sage -t --long local/lib/python2.7/site-
packages/sagenb-0.10.7.2-py2.7.egg/sagenb/misc/sphinxify.py
**********************************************************************
File "local/lib/python2.7/site-
packages/sagenb-0.10.7.2-py2.7.egg/sagenb/misc/sphinxify.py", line 69,
in sagenb.misc.sphinxify.sphinxify
Failed example:
    sphinxify('A test')
Expected:
    '\n<div class="docstring">\n    \n  <p>A test</p>\n\n\n</div>'
Got:
    '<div class="docstring">\n    \n  <p>A test</p>\n\n\n</div>'
**********************************************************************
File "local/lib/python2.7/site-
packages/sagenb-0.10.7.2-py2.7.egg/sagenb/misc/sphinxify.py", line 71,
in sagenb.misc.sphinxify.sphinxify
Failed example:
    sphinxify('**Testing**\n`monospace`')
Expected:
    '\n<div class="docstring"...<strong>Testing</strong>\n<span
class="math"...</p>\n\n\n</div>'
Got:
    '<div class="docstring">\n    \n  <p><strong>Testing</strong>\n<span
class="math">monospace</span></p>\n\n\n</div>'
**********************************************************************
File "local/lib/python2.7/site-
packages/sagenb-0.10.7.2-py2.7.egg/sagenb/misc/sphinxify.py", line 73,
in sagenb.misc.sphinxify.sphinxify
Failed example:
    sphinxify('`x=y`')
Expected:
    '\n<div class="docstring">\n    \n  <p><span
class="math">x=y</span></p>\n\n\n</div>'
Got:
    '<div class="docstring">\n    \n  <p><span
class="math">x=y</span></p>\n\n\n</div>'
**********************************************************************
}}}

URL: http://trac.sagemath.org/17268
Reported by: jdemeyer
Ticket author(s): Jeroen Demeyer
Reviewer(s): Volker Braun