SVGHMI: Fix update of HMI tree in UI when loading from XML at start. Removed some dead code left after split of svghmi.py into svghmi.py+ui.py.
<xsd:element name="Xenomai">
<xsd:complexType>
%(toolchain_gcc)s
<xsd:attribute name="XenoConfig" type="xsd:string" use="optional" default="xeno-config"/>
</xsd:complexType>
</xsd:element>