Remove gvir_config_domain_cpu_get_features() from sym file
Remove gvir_config_domain_cpu_get_features() from sym file

This method was never exported. GVirConfigDomainCpu inherits from
GVirConfigCapabilitiesCpu so gvir_config_capabilities_cpu_get_features()
should be used to get these features (this calls the virtual method
GVirConfigCapabilities::get_features() which GVirConfigDomainCpu
implements).

libvirt/libvirt-glib,libvirt/libvirt-glib,libvirt/libvirt-glib