Improve guard so it works for no eof new line

compiler/sbt.vim

@@ -1,4 +1,5 @@
 if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'scala') == -1
+
 " Vim compiler file
 " Language:             Scala SBT (http://www.scala-sbt.org/)
 " Maintainer:           Derek Wyatt
@@ -29,4 +30,5 @@ let &cpo = s:cpo_save
 unlet s:cpo_save
 
 " vim:set sw=2 sts=2 ts=8 et:
+
 endif