Unforce tzinfo from AS

Signed-off-by: José Valim <jose.valim@gmail.com>

actionpack/actionpack.gemspec

@@ -25,5 +25,6 @@ Gem::Specification.new do |s|
   s.add_dependency('rack',          '~> 1.1.0')
   s.add_dependency('rack-test',     '~> 0.5.4')
   s.add_dependency('rack-mount',    '~> 0.6.3')
+  s.add_dependency('tzinfo',        '~> 0.3.16')
   s.add_dependency('erubis',        '~> 2.6.5')
 end

activerecord/activerecord.gemspec

@@ -24,4 +24,5 @@ Gem::Specification.new do |s|
   s.add_dependency('activesupport', version)
   s.add_dependency('activemodel',   version)
   s.add_dependency('arel',          '~> 0.3.3')
+  s.add_dependency('tzinfo',        '~> 0.3.16')
 end

activesupport/activesupport.gemspec

@@ -19,7 +19,6 @@ Gem::Specification.new do |s|
 
   s.has_rdoc = true
 
-  s.add_dependency('tzinfo',          '~> 0.3.16')
   s.add_dependency('builder',         '~> 2.1.2')
   s.add_dependency('memcache-client', '>= 1.7.5')
 end

activesupport/lib/active_support/values/time_zone.rb

@@ -1,5 +1,11 @@
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/object/try'
+begin
+  require 'tzinfo'
+rescue LoadError => e
+  $stderr.puts "You don't have tzinfo installed in your application. Please add it to your Gemfile and run bundle install"
+  raise e
+end
 
 # The TimeZone class serves as a wrapper around TZInfo::Timezone instances. It allows us to do the following:
 #
@@ -313,7 +319,7 @@ module ActiveSupport
 
     # TODO: Preload instead of lazy load for thread safety
     def self.find_tzinfo(name)
-      require 'tzinfo' unless defined?(::TZInfo)
+      require 'active_support/tzinfo' unless defined?(::TZInfo)
       ::TZInfo::TimezoneProxy.new(MAPPING[name] || name)
     end