[HOTFIX][SPARK-12000] Add missing quotes in Jekyll API docs plugin.

JoshRosen · JoshRosen · commit 86a46ce686cd · 2015-11-30T18:26:48.000-08:00
I accidentally omitted these as part of apache#10049.
diff --git a/docs/_plugins/copy_api_dirs.rb b/docs/_plugins/copy_api_dirs.rb
@@ -117,7 +117,7 @@
 
   puts "Moving to python/docs directory and building sphinx."
   cd("../python/docs")
-  system(make html) || raise("Python doc generation failed")
+  system("make html") || raise("Python doc generation failed")
 
   puts "Moving back into home dir."
   cd("../../")
