add courses crashes on cancel when course title contains a tilde

[Damian Javier Solalinde]

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Por favor, complete los pasos para reproducir el error aquí:
Escuela/Agregar Curso/
Agregar un curso con acentos en el título, guardar. Luego hacer clic en agregar curso, y luego clic en cancelar.

School/Courses/Add course
Add a course with accent in the title. Save. Then click in add course, then click in cancel

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Exception

UnicodeEncodeError: 'ascii' codec can't encode character u'\xe1' in position 52: ordinal not in range(128)

Traceback

File "/usr/lib/python2.7/dist-packages/zope/publisher/publish.py", line 132, in publish
  result = publication.callObject(request, obj)
File "/usr/lib/python2.7/dist-packages/zope/app/publication/zopepublication.py", line 205, in callObject
  return mapply(ob, request.getPositionalArguments(), request)
File "/usr/lib/python2.7/dist-packages/zope/publisher/publish.py", line 107, in mapply
  return debug_call(obj, args)
Extra information: schooltool.skin.flourish.zcml_content.FlourishCourseAddView_addSchoolToolCourse.html object at 0x7f5259483110
File "/usr/lib/python2.7/dist-packages/zope/publisher/publish.py", line 113, in debug_call
  return obj(*args)
File "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/page.py", line 70, in __call__
  self.update()
File "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/form.py", line 72, in update
  super(AddForm, self).update()
File "/usr/lib/python2.7/dist-packages/schooltool/skin/flourish/form.py", line 55, in update
  super(Form, self).update()
File "/usr/lib/python2.7/dist-packages/z3c/form/form.py", line 211, in update
  self.actions.execute()
File "/usr/lib/python2.7/dist-packages/z3c/form/action.py", line 99, in execute
  result = handler()
File "/usr/lib/python2.7/dist-packages/z3c/form/button.py", line 315, in __call__
  return handler(self.form, self.action)
File "/usr/lib/python2.7/dist-packages/z3c/form/button.py", line 170, in __call__
  return self.func(form, action)
File "/usr/lib/python2.7/dist-packages/schooltool/course/browser/course.py", line 739, in handle_cancel_action
  self.request.response.redirect(url)
File "/usr/lib/python2.7/dist-packages/zope/publisher/browser.py", line 759, in redirect
  return super(BrowserResponse, self).redirect(location, status, trusted)
File "/usr/lib/python2.7/dist-packages/zope/publisher/http.py", line 877, in redirect
  location = str(location)

Modules

schooltool 2.8.5 (/usr/lib/python2.7/dist-packages)
schooltool.cando 2.8.2 (/usr/lib/python2.7/dist-packages)
schooltool.gradebook 2.8.4.1 (/usr/lib/python2.7/dist-packages)
schooltool.intervention 2.7.0 (/usr/lib/python2.7/dist-packages)
schooltool.lyceum.journal 2.8.2.1 (/usr/lib/python2.7/dist-packages)

Runtime

Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2]
Linux javier-Inspiron-N4010 3.19.0-43-generic #49~14.04.1-Ubuntu SMP Thu Dec 31 15:44:49 UTC 2015 x86_64 x86_64
Filesystem encoding ANSI_X3.4-1968, preferred ANSI_X3.4-1968