update_engine: fixed remaining linter and some spelling errors

Fixed remaining errors from cpplint as well as some spelling errors
mostly in comments.

BUG=None
TEST=FEATURES=test emerge-link update_engine

Change-Id: I484988ab846ac5a3c68c016ddccfb247f225ec27
Reviewed-on: https://chromium-review.googlesource.com/208897
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/omaha_response_handler_action_unittest.cc b/omaha_response_handler_action_unittest.cc
index 80aad60..51eab78 100644
--- a/omaha_response_handler_action_unittest.cc
+++ b/omaha_response_handler_action_unittest.cc
@@ -99,7 +99,7 @@
   processor.EnqueueAction(&collector_action);
   processor.StartProcessing();
   EXPECT_TRUE(!processor.IsRunning())
-      << "Update test to handle non-asynch actions";
+      << "Update test to handle non-async actions";
   if (out)
     *out = collector_action.object();
   EXPECT_TRUE(delegate.code_set_);