system/slack-utils: Modified SlackBuild for ruby-2.2.3.

Signed-off-by: David Spencer <baildon.research@googlemail.com>

system/slack-utils/slack-utils.SlackBuild

@@ -49,6 +49,9 @@ rm -rf $PRGNAM-$VERSION
 tar xvf $CWD/$PRGNAM-$VERSION.tar.gz
 cd $PRGNAM-$VERSION
 
+# Fix renamed Config -> RbConfig
+sed -i -e 's/::Config::CONFIG/::RbConfig::CONFIG/' setup.rb
+
 ruby setup.rb config \
 	--prefix=/usr \
 	--sysconfdir=/etc \