WireCloud doesn't work with old versions of requests

[aarranz]

WireCloud 1.0.0 fails to load wirecloud.fiware when using requests from v2.1 to v2.8.1:

$ python manage.py runserver 0.0.0.0:8000
Performing system checks...

Error importing wirecloud.fiware.plugins (cannot import name ConnectTimeout). Any WireCloud plugin available through the wirecloud.fiware app will be ignored
Error importing wirecloud.fiware.plugins (cannot import name ConnectTimeout). Any WireCloud plugin available through the wirecloud.fiware app will be ignored
System check identified no issues (0 silenced).
September 26, 2016 - 11:37:44
Django version 1.10.1, using settings 'wirecloud_instance.settings'
Starting development server at http://0.0.0.0:8000/
Quit the server with CONTROL-C.

WireCloud works as expected when using requests 2.9.0+