JAXP pom change

[Tom Zeller]

> OpenSAML appears to have built and tested cleanly with no JAXP endorsement
> or compile time deps, the IdP is running now. Assume that's clean, I will
> check in, but if Jenkins freaks out, that's why.

The idp.xml.securityManager property needs to change in
idp.properties, correct ?

(I changed it locally, which resulted in an "invalid context"
SAXParseException on a beans def file)