RFR(S): JDK-8029172: warnings from b117 for hotspot.agent.src.os.linux: JNI exception pending

[Dmitry Samersoff]

Please review:

http://cr.openjdk.java.net/~dsamersoff/JDK-8029172/webrev.01/

Added more exception checks to agent/src/os/linux/LinuxDebuggerLocal.c

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