drop gettext from jruby gems

this gem was likely added to support the (brief) module localization
effort, in addition to fast_gettext, but it's probably unused by now

Author: jcharaoui

resources/ext/build-scripts/jruby-gem-list.txt

@@ -2,7 +2,6 @@ semantic_puppet 1.1.0
 hocon 1.4.0
 text 1.3.1
 locale 2.1.4
-gettext 3.4.9
 fast_gettext 2.4.0
 concurrent-ruby 1.2.3
 deep_merge 1.2.2