Fix casing in spring mvc namespace attributes

Update "enableMatrixVariables" and "ignoreDefaultModelOnRedirect" to
use the more conventional XML form "enable-matrix-variables" and
"ignore-default-model-on-redirect".

Both forms are now supported by `AnnotationDrivenBeanDefinitionParser`,
with newer names being defined in the 4.0 XSD and the older names
remaining in the 3.2 XSD.

Issue: SPR-11136