RFR(S): JDK-8029465 warnings from b118 for jdk.src.share.native.sun.management: JNI exception pending

[Dmitry Samersoff]

Please review a small fix:

http://cr.openjdk.java.net/~dsamersoff/JDK-8029465/webrev.01/

Added couple of missed exception checks.

-- 
Dmitry Samersoff
Oracle Java development team, Saint Petersburg, Russia
* I would love to change the world, but they won't give me the sources.