Require open-uri in DocsCLI#download_docs

lib/tasks/docs.thor

@@ -1,8 +1,3 @@
-# Prevents this error: https://gist.github.com/nitay/0cbf5ccb2bc611f627e5
-# See also: http://stackoverflow.com/questions/694115/why-does-ruby-open-uris-open-return-a-stringio-in-my-unit-test-but-a-fileio-in
-OpenURI::Buffer.send :remove_const, 'StringMax' if OpenURI::Buffer.const_defined?('StringMax')
-OpenURI::Buffer.const_set 'StringMax', 0
-
 class DocsCLI < Thor
   include Thor::Actions
 
@@ -139,6 +134,11 @@ class DocsCLI < Thor
   end
 
   def download_docs(docs)
+    # Don't allow downloaded files to be created as StringIO
+    require 'open-uri'
+    OpenURI::Buffer.send :remove_const, 'StringMax' if OpenURI::Buffer.const_defined?('StringMax')
+    OpenURI::Buffer.const_set 'StringMax', 0
+
     require 'thread'
     length = docs.length
     i = 0