RFR: 8231126: libxslt.md has incorrect version string

[Kevin Rushforth]

Guru,

Please review the following simple fix to correct the version number 
string in libxslt.md:

https://bugs.openjdk.java.net/browse/JDK-8231126
https://github.com/javafxports/openjdk-jfx/pull/593

Thanks.

-- Kevin