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/update_manager/boxed_value.cc b/update_manager/boxed_value.cc
index 512f7a8..8200879 100644
--- a/update_manager/boxed_value.cc
+++ b/update_manager/boxed_value.cc
@@ -137,7 +137,7 @@
 string BoxedValue::ValuePrinter<Stage>(const void *value) {
   const Stage* val = reinterpret_cast<const Stage*>(value);
   switch (*val) {
-   case Stage::kIdle:
+    case Stage::kIdle:
       return "Idle";
     case Stage::kCheckingForUpdate:
       return "Checking For Update";