[8u-dev] RFA: 8074812 More specific error message when the .java_pid well-known file is not secure

[David Buck]

Hi!

Please approve the backport of this small fix to 8u-dev. The JDK 9 patch 
applies cleanly as-is to the 8u-dev forest after file pathname unshuffling .

bug report:
https://bugs.openjdk.java.net/browse/JDK-8074812

jdk 9 changeset:
http://hg.openjdk.java.net/jdk9/jdk9/jdk/rev/6bc2a02b0f45

jdk 9 review thread:
http://mail.openjdk.java.net/pipermail/serviceability-dev/2015-March/016878.html

I have manually tested the fix on Linux, Solaris, and macOS hosts. 
Default, hotspot, and core jprt testsets also run and passed.

Cheers,
-Buck