shill: Fix most of warnings from cpplint

Fix most cpplinter's warnings. On a few occasisions, the warnings
produced were false-positives, so added explicit // NOLINT comment
overrides.

There were a few instances of disallowed non-const reference usage
(reported as runtime/reference error by cpplint) for
"DBus::Error &error" which should potentially be changed
to pointers to comply with C++ coding style but I will let Shill
owners do that since there is quite a few of those and the
change isn't brain-dead simple...

BUG=None
TEST=platform2 still compiles and all unit tests pass.

Change-Id: Ic2e31896aa13d20eeb1a85dee74f3db8cccfde2e
Reviewed-on: https://chromium-review.googlesource.com/204164
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/hook_table.h b/hook_table.h
index bf9d4dc..bb261ec 100644
--- a/hook_table.h
+++ b/hook_table.h
@@ -103,7 +103,7 @@
 
   // This callback is created in Run() and is queued to the event dispatcher to
   // run after a timeout period.  If all the actions complete before the
-  // timeout, then this callback is cancelled.
+  // timeout, then this callback is canceled.
   base::CancelableClosure timeout_callback_;
 
   // Used for setting a timeout action to run in case all the actions do not