[7u6] RFR (JAXP) : 7144423: StAX EventReader swallows the cause of error

[Joe Wang]

Hi,

This is patch to make sure the cause of the error is properly reported.  
It has been in jaxp since Feb.

webrev: http://cr.openjdk.java.net/~joehw/7u6/7143711/webrev/

Please review.

Thanks,
Joe