cubicweb #2847207 failure to handle multiple files from the web client [validation pending]

e.g.:

files = FileField(widget=fw.FileInput(attrs={'multiple': 'multiple'}))

The response dies pretty quickly:

File "/home/auc/confs/simulagora/cubicweb/etwist/server.py", line 145, in render_request
   return self._render_request(request)
 File "/home/auc/confs/simulagora/cubicweb/etwist/server.py", line 167, in _render_request
   req = CubicWebTwistedRequestAdapter(request, self.appli.vreg, https)
 File "/home/auc/confs/simulagora/cubicweb/etwist/request.py", line 37, in __init__
   vreg, https, req.args, headers=req.received_headers)
 File "/home/auc/confs/simulagora/cubicweb/web/request.py", line 118, in __init__
   self.setup_params(form)
 File "/home/auc/confs/simulagora/cubicweb/web/request.py", line 253, in setup_params
   val = [unicode(x, encoding) for x in val]
 File "/usr/lib/python2.6/encodings/utf_8.py", line 16, in decode
   return codecs.utf_8_decode(input, errors, True)
prioritynormal
typebug
done in3.18.0
load0.500
load left0.000
closed by#01124cfd4b1f [etwist] fix handling of multiple files per field
patch[etwist] fix handling of multiple files per field (closes #2847207) [applied]