audit: fix false-positive for '--with-check' from 'depends_on "check" => :optional' (#188)

Fixes #170

Library/Homebrew/cmd/audit.rb

@@ -391,10 +391,12 @@ class FormulaAuditor
       end
 
       if o.name =~ /^with(out)?-(?:checks?|tests)$/
+        unless formula.deps.any? { |d| d.name == "check" && (d.optional? || d.recommended?) }
           problem "Use '--with#{$1}-test' instead of '--#{o.name}'. Migrate '--#{o.name}' with `deprecated_option`."
         end
       end
     end
+  end
 
   def audit_desc
     # For now, only check the description when using `--strict`