Ignore format of common Ruby files

By redefining the `Exclude` list for `FileName` in 75dd7d5 we overrode
the default list. Fix this by including the defaults explicitly.

Change-Id: I7e1cea7ddc31c17810819b57889c25d9b1db725f
Reviewed-on: http://gerrit.causes.com/36729
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>