RFR: JDK-8180322 Move JNI spec to specs directory

[Mandy Chung]

> On Jun 1, 2017, at 5:46 AM, Magnus Ihse Bursie <magnus.ihse.bursie at oracle.com> wrote:
> 
> The JNI spec will move to a new place in the "specs" directory in the docs image, and links to it needs to be updated.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8180322
> WebRev: http://cr.openjdk.java.net/~ihse/JDK-8180322-move-jni-spec/webrev.01
> 
> This is a noreg-docs fix and will be pushed to jdk9.

Looks okay to me.

Mandy