Use module_function instead of class << self

The `Utils` module had an unnecessary extra level of indention due to
its use of `class << self` to make its helpers all class-level
functions.

Fix this by using the `module_function` helper, which accomplishes the
same thing.

Change-Id: I6194f394e111a6e7dac2672189472eb53ae62f04
Reviewed-on: http://gerrit.causes.com/42352
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>