RFR (JDK10/JAXP) 8191938: Fix lint warnings in JAXP repo: a few Deprecation warrnings and enable -Xlint:all

[Joe Wang]

Hi,

Please review a fix for a few more deprecation warnings. Compiling with 
-Xlint:all showed that these were the last few warnings. We can then 
enable -Xlint:all for the java.xml module.

JBS: https://bugs.openjdk.java.net/browse/JDK-8191938
webrevs: http://cr.openjdk.java.net/~joehw/jdk10/8191938/webrev/

Thanks,
Joe