Use ActiveSupport's try as some versions of backports have wrong implementation

sinatra-contrib/lib/sinatra/capture.rb

@@ -1,6 +1,6 @@
 require 'sinatra/base'
 require 'sinatra/engine_tracking'
-require 'backports'
+require 'active_support/core_ext/object/try.rb'
 
 module Sinatra
   #

sinatra-contrib/sinatra-contrib.gemspec

@@ -24,6 +24,7 @@ Gem::Specification.new do |s|
   s.add_dependency "sinatra", version
   s.add_dependency "mustermann", "~> 1.0"
   s.add_dependency "backports", "~> 2.8.2"
+  s.add_dependency "activesupport", ">= 4.0.0"
   s.add_dependency "tilt",      ">= 1.3", "< 3"
   s.add_dependency "rack-protection", version
   s.add_dependency "multi_json"