Remove tainted calls

[adfoster-r7]

The Ruby core team has deprecated the taint mechanism in Ruby 2.7 and will remove it in Ruby 3.2

Ruby had Taint checking which is originally introduced in Perl. https://en.wikipedia.org/wiki/Taint_checking

It was intended to provide a useful tool for handle objects which are come from outside. Input data is set as tainted by default and call untaint if you checked or filtered the value. Some people used this feature in the age of CGI.

But these days, no one use the mechanism and input libraries usually doesn't support it.

• https://bugs.ruby-lang.org/issues/16131

In Ruby 2.7 this functionality is now noop:

  VALUE
  rb_obj_taint(VALUE obj)
  {
-     if (!OBJ_TAINTED(obj) && OBJ_TAINTABLE(obj)) {
-        rb_check_frozen(obj);
-        OBJ_TAINT(obj);
-     }
+     rb_warning("Object#taint is deprecated and will be removed in Ruby 3.2.");
      return obj;
  }

Associated Ruby core code change: https://github.com/ruby/ruby/pull/2476

Example warnings:

/Users/user/.rvm/gems/ruby-2.7.0/gems/rex-core-0.1.14/lib/rex/file.rb:133: warning: Object#taint is deprecated and will be removed in Ruby 3.2. /Users/user/.rvm/gems/ruby-2.7.0/gems/rex-core-0.1.14/lib/rex/file.rb:133: warning: Object#taint is deprecated and will be removed in Ruby 3.2. /Users/user/.rvm/gems/ruby-2.7.0/gems/rex-core-0.1.14/lib/rex/file.rb:148: warning: Object#untaint is deprecated and will be removed in Ruby 3.2. /Users/user/.rvm/gems/ruby-2.7.0/gems/rex-core-0.1.14/lib/rex/file.rb:133: warning: Object#taint is deprecated and will be removed in Ruby 3.2.

https://github.com/rapid7/metasploit-framework/issues/14666