hg: bsd-port/jdk8/jdk: - OpenBSD's libiconv is built without LIBICONV_PLUG defined so remove

[kurt]

Changeset: d2f7ffb07999
Author:    kurt
Date:      2015-06-18 10:52 -0400
URL:       http://hg.openjdk.java.net/bsd-port/jdk8/jdk/rev/d2f7ffb07999

- OpenBSD's libiconv is built without LIBICONV_PLUG defined so remove
it for OpenBSD only.
- Add missing link path to iconv for libsplashscreen for *bsd

! make/lib/Awt2dLibraries.gmk
! make/lib/CoreLibraries.gmk
! make/lib/ServiceabilityLibraries.gmk