#294 [Taurus4] Exception in taurusconfigurationpanel with eval attr

[Carlos Falcon]

A lot of AttributeError are raised when open a taurusconfiguration panel with an eval attribute.

To reproduce, with develop :
* Launch taurusform eval:1
* right-click in the label and select "Configuration" --> "All"

Traceback (most recent call last):
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/util/taurusaction.py", line 249, in actionTriggered
    d.setModel(taurus_widget.getModelName())
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/dialog/taurusconfigurationdialog.py", line 64, in setModel
    self._panel.setModel(model)
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/panel/taurusconfigurationpanel.py", line 221, in setModel
    self._ui.labelConfig.setModel(model + 'label')
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/panel/taurusconfigurationpanel.py", line 143, in setModel
    TaurusBaseWritableWidget.setModel(self, model)
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/base/taurusbase.py", line 946, in setModel
    self.setModelCheck(model)
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/base/taurusbase.py", line 1229, in setModelCheck
    TaurusBaseComponent.setModelCheck(self, model, check)
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/base/taurusbase.py", line 978, in setModelCheck
    self.setModelName(model, parent_widget)
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/base/taurusbase.py", line 498, in setModelName
    self._attach()
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/base/taurusbase.py", line 788, in _attach
    self.postAttach()
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/panel/taurusconfigurationpanel.py", line 74, in postAttach
    self.setValue(v)
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/panel/taurusconfigurationpanel.py", line 96, in setValue
    v_str = str(self.getValue())
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/panel/taurusconfigurationpanel.py", line 123, in getValue
    return self._getAttrInfoExMember(self.modelFragmentName)
  File "/home/cfalcon/tools/taurus.git/lib/taurus/qt/qtgui/panel/taurusconfigurationpanel.py", line 103, in _getAttrInfoExMember
    attrInfoEx = model_obj.getAttributeInfoEx()
AttributeError: 'EvaluationAttribute' object has no attribute 'getAttributeInfoEx'

[Carlos Pascual]

Basically, the configuration dialog is tango-centric.
This should be an entry-point for scheme plugins to provide their own configuration.

As a workaround, the configuration action should be disabled in the label widget for models other than tango