Fix doctests that want write access to $SAGE_ROOT

Imported from <a href="http://trac.sagemath.org/sage_trac/ticket/5155">trac #5155</a>.



Reported by: mabshoff

Component: scripts

CC: lftabera,, leif

Report Upstream: N/A

Authors: Mike Hansen, Jeroen Demeyer, John Palmieri

Dependencies: <a href="http://trac.sagemath.org/sage_trac/ticket/13157">trac #13157</a>, <a href="http://trac.sagemath.org/sage_trac/ticket/13397">trac #13397</a>, <a href="http://trac.sagemath.org/sage_trac/ticket/13452">trac #13452</a>, <a href="http://trac.sagemath.org/sage_trac/ticket/13407">trac #13407</a>, <a href="http://trac.sagemath.org/sage_trac/ticket/13459">trac #13459</a>, <a href="http://trac.sagemath.org/sage_trac/ticket/13457">trac #13457</a>, <a href="http://trac.sagemath.org/sage_trac/ticket/13123">trac #13123</a>, <a href="http://trac.sagemath.org/sage_trac/ticket/13887">trac #13887</a>

Work issues: 

Reviewers: François Bissey

Merged in: sage-5.7.beta0

Attachments: <ol><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/5155/5155_root.patch">5155_root.patch: </a> by jdemeyer at 20120916T18:42:35</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/5155/5155_sage_location.patch">5155_sage_location.patch: </a> by jdemeyer at 20120916T18:44:12</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/5155/5155_sagelib.patch">5155_sagelib.patch: </a> by jdemeyer at 20121219T21:01:07</li></ol>