Manual roll of raw_io output -> output_text refactor

BUG=686280,664352
TBR=iannucci

Change-Id: Ibd1feadffc440ea01790abe2bc73fc6a69092f54
Reviewed-on: https://chromium-review.googlesource.com/437821Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Commit-Queue: Stephen Martinis <martiniss@chromium.org>

infra/config/recipes.cfg

@@ -5,5 +5,5 @@ deps {
   project_id: "recipe_engine"
   url: "https://chromium.googlesource.com/external/github.com/luci/recipes-py.git"
   branch: "master"
-  revision: "5d4666c5340082e7bfad85ee01d47ebbc48aeab6"
+  revision: "9456147555cc76adec014709e02928b620d7d8d9"
 }

recipe_modules/tryserver/example.py

@@ -48,7 +48,7 @@ def RunSteps(api):
 
 def GenTests(api):
   description_step = api.override_step_data(
-      'git_cl description', stdout=api.raw_io.output('foobar'))
+      'git_cl description', stdout=api.raw_io.output_text('foobar'))
   yield (api.test('with_git_patch') +
          api.properties(
               path_config='buildbot',