RFR: JDK-8221525: jpackage fails with non-ASCII characters in --copyright

[Alexander Matveev]

Please review the jpackage fix for bug [1] at [2].

This is a fix for the JDK-8200758-branch branch of the open sandbox 
repository (jpackage).

- .properties file was written in default encoding 
(file.encoding=Cp1252). Native code was expecting UTF-8 and thus was
not able to read non-ASCII characters correctly. Fixed by writing file 
using UTF-8.

[1] https://bugs.openjdk.java.net/browse/JDK-8221525

[2] http://cr.openjdk.java.net/~almatvee/8221525/webrev.00/

Thanks,
Alexander