Quiet Rubocop lint in RailsSchemaUpToDate hook

The complexity here is necessary, and isolated such that we don't need
to worry about it.

Change-Id: I5e8e1f8dae188d861ea4221acad2b116d65f7e26
Reviewed-on: http://gerrit.causes.com/40384
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>