Remove unused argument for `format` in `Security/YAMLLoad` cop
Remove unused argument for `format` in `Security/YAMLLoad` cop

With `ruby -w`, a warning is occurred in `Security/YAMLLoad` cop.

```sh
$ RUBYOPT=-w
/home/pocke/.gem/ruby/2.4.0/gems/parser-2.3.3.1/lib/parser/lexer.rb:10922: warning: assigned but unused variable - testEof
/home/pocke/.gem/ruby/2.4.0/gems/rubocop-0.47.1/lib/rubocop/magic_comment.rb:124: warning: `frozen_string_literal' is ignored after any tokens
Inspecting 888 files
............................/home/pocke/.gem/ruby/2.4.0/gems/rubocop-0.47.1/lib/rubocop/cop/security/yaml_load.rb:27: warning: too many arguments for format string
........................................................................................................................................................................................................................................................................................................................................................................................................................................................./home/pocke/.gem/ruby/2.4.0/gems/rubocop-0.47.1/lib/rubocop/cop/security/yaml_load.rb:27: warning: too many arguments for format string
...................................................................................................................................................................................................................................................................................................................................................................................................................................

888 files inspected, no offenses detected
```

The argument is not used. So, I've remove it.

Note
-----

Other warnings are occurred, however, this change ignores the warnings.

- `/home/pocke/.gem/ruby/2.4.0/gems/parser-2.3.3.1/lib/parser/lexer.rb:10922: warning: assigned but unused variable - testEof`
  - It's a parser gem's problem.
- `/home/pocke/.gem/ruby/2.4.0/gems/rubocop-0.47.1/lib/rubocop/magic_comment.rb:124: warning: `frozen_string_literal' is ignored after any tokens`
  - It's a false positive.

mikegee/rubocop,bbatsov/rubocop,deivid-rodriguez/rubocop,bbatsov/rubocop,smakagon/rubocop,pocke/rubocop,petehamilton/rubocop,panthomakos/rubocop,palkan/rubocop,backus/rubocop,scottmatthewman/rubocop,jmks/rubocop,bquorning/rubocop,NobodysNightmare/rubocop,haziqhafizuddin/rubocop,sue445/rubocop,tejasbubane/rubocop,tdeo/rubocop,petehamilton/rubocop,smakagon/rubocop,rrosenblum/rubocop,jmks/rubocop,alexcstark/rubocop,jfelchner/rubocop,lumeet/rubocop,vergenzt/rubocop,bankair/rubocop,maxjacobson/rubocop,ilansh/rubocop,b-t-g/rubocop,urbanautomaton/rubocop,bquorning/rubocop,backus/rubocop,mclark/rubocop,akihiro17/rubocop,urbanautomaton/rubocop,pocke/rubocop,meganemura/rubocop,maxjacobson/rubocop,jfelchner/rubocop,meganemura/rubocop,haziqhafizuddin/rubocop,iGEL/rubocop,rrosenblum/rubocop,mikegee/rubocop,petehamilton/rubocop,rtlechow/rubocop,scottmatthewman/rubocop,bquorning/rubocop,deivid-rodriguez/rubocop,alexcstark/rubocop,tejasbubane/rubocop,meganemura/rubocop,b-t-g/rubocop,vergenzt/rubocop,tejasbubane/rubocop,rtlechow/rubocop,tdeo/rubocop,Drenmi/rubocop,Drenmi/rubocop,sue445/rubocop,ilansh/rubocop,vergenzt/rubocop,iGEL/rubocop,sue445/rubocop,jmks/rubocop,tdeo/rubocop,akihiro17/rubocop,mikegee/rubocop,akihiro17/rubocop,deivid-rodriguez/rubocop,panthomakos/rubocop,maxjacobson/rubocop,NobodysNightmare/rubocop,palkan/rubocop,mclark/rubocop,bankair/rubocop,jfelchner/rubocop,lumeet/rubocop,palkan/rubocop,panthomakos/rubocop,rrosenblum/rubocop