LabelPlugValueWidget : Don't disable label for read only plugs.
LabelPlugValueWidget : Don't disable label for read only plugs.

The popup menu still has useful items (not least of which is Unlock) even for read only plugs, and we need to be enabled to provide access to them.

lucienfostier/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,hradec/gaffer,hradec/gaffer,ImageEngine/gaffer,appleseedhq/gaffer,boberfly/gaffer,GafferHQ/gaffer,ivanimanishi/gaffer,johnhaddon/gaffer,ivanimanishi/gaffer,chippey/gaffer,boberfly/gaffer,appleseedhq/gaffer,ImageEngine/gaffer,andrewkaufman/gaffer,ImageEngine/gaffer,hradec/gaffer,ivanimanishi/gaffer,johnhaddon/gaffer,lucienfostier/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,chippey/gaffer,ivanimanishi/gaffer,boberfly/gaffer,hradec/gaffer,appleseedhq/gaffer,GafferHQ/gaffer,ImageEngine/gaffer,chippey/gaffer,andrewkaufman/gaffer,hradec/gaffer,boberfly/gaffer,lucienfostier/gaffer,appleseedhq/gaffer,lucienfostier/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,chippey/gaffer