RFR: (XXS): JDK-8175135: Header template correction for year

[Gerard Ziemski]

hi all,

Please review this extra small bug fix, that adds comma to the copyright header as required by the GPL header template.

Verified with the jdk/make/scripts/lic_check.sh script and JPRT build.

issue:  https://bugs.openjdk.java.net/browse/JDK-8175135
webrev: http://cr.openjdk.java.net/~gziemski/8175135_rev1/

Thank you