include otf extension in fontawesome test

test/acceptance/fixtures/examples/fontawesome_xelatex/main.tex

@@ -1,4 +1,8 @@
 \documentclass{article}
+\usepackage{fontspec}
+\defaultfontfeatures{Extension = .otf} % this is needed because
+                                       % fontawesome package loads by
+                                       % font name only
 \usepackage{fontawesome}
 
 \begin{document}