(PUP-11974) Only warn when Ruby's verbose is enabled

In ruby 2.7.x, the rb_file_exists_p and rb_dir_exists_p methods call
rb_warning to log that the methods are deprecated[1][2] However, the
rb_warning method is a noop if $VERBOSE is nil or false[3] To preserve
the same behavior, only warn when $VERBOSE is truthy. Also include the
class name and path in the warning so we can identify and fix the issue.

[1] https://github.com/ruby/ruby/blob/1f4d4558484b370999954f3ede7e3aa3a3a01ef3/file.c#L1819
[2] https://github.com/ruby/ruby/blob/1f4d4558484b370999954f3ede7e3aa3a3a01ef3/dir.c#L3301
[3] https://github.com/ruby/ruby/blob/1f4d4558484b370999954f3ede7e3aa3a3a01ef3/error.c#L336-L338

Author: joshcooper

lib/puppet/util/monkey_patches.rb

@@ -33,7 +33,7 @@ def daemonize
 unless Dir.singleton_methods.include?(:exists?)
   class Dir
     def self.exists?(file_name)
-      warn('exists? is a deprecated name, use exist? instead')
+      warn("Dir.exists?('#{file_name}') is deprecated, use Dir.exist? instead") if $VERBOSE
       Dir.exist?(file_name)
     end
   end
@@ -42,7 +42,7 @@ def self.exists?(file_name)
 unless File.singleton_methods.include?(:exists?)
   class File
     def self.exists?(file_name)
-      warn('exists? is a deprecated name, use exist? instead')
+      warn("File.exists?('#{file_name}') is deprecated, use File.exist? instead") if $VERBOSE
       File.exist?(file_name)
     end
   end