Tell Travis to use system version of Nokogiri.

gkellogg · gkellogg · commit 42bc210a773f · 2019-01-12T12:34:56.000-08:00
diff --git a/.travis.yml b/.travis.yml
@@ -6,6 +6,8 @@ before_install:
   - 'gem update bundler --conservative'
 env:
   - CI=true
+  global:
+    - NOKOGIRI_USE_SYSTEM_LIBRARIES=true
 gemfile:
   - Gemfile
   - Gemfile-pure
