gc_feature_node: don't register EnumEntry nodes.
gc_feature_node: don't register EnumEntry nodes.

EnumEntry node name may conflict with a feature. Specification
says one needs to pre-parse the genicam file and replace the
EnumEntry name by EnumerationName_EnumEntryName.

AnilRamachandran/aravis,AnilRamachandran/aravis,lu-zero/aravis,AnilRamachandran/aravis,AravisProject/aravis,AravisProject/aravis,AravisProject/aravis,lu-zero/aravis,AnilRamachandran/aravis,AravisProject/aravis,lu-zero/aravis,lu-zero/aravis,AravisProject/aravis,AnilRamachandran/aravis,lu-zero/aravis