Proc.new: change deprecation warning for clarity (issue #15539)

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67519 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/ruby/core/kernel/proc_spec.rb

@@ -56,7 +56,7 @@ describe "Kernel#proc" do
 
       -> {
         some_method { "hello" }
-      }.should complain(/tried to create Proc object without a block/)
+      }.should complain(/Capturing the given block using Proc.new is deprecated/)
     end
   end