Move sshpublisher require into the rake tasks that use it so ruby 1.9…

… and macruby don't need the rake gem installed

activesupport/Rakefile

@@ -1,7 +1,6 @@
 require 'rake/testtask'
 require 'rake/rdoctask'
 require 'rake/gempackagetask'
-require 'rake/contrib/sshpublisher'
 
 require File.join(File.dirname(__FILE__), 'lib', 'active_support', 'version')
 
@@ -65,12 +64,14 @@ end
 
 desc "Publish the beta gem"
 task :pgem => [:package] do
+  require 'rake/contrib/sshpublisher'
   Rake::SshFilePublisher.new("gems.rubyonrails.org", "/u/sites/gems/gems", "pkg", "#{PKG_FILE_NAME}.gem").upload
   `ssh gems.rubyonrails.org '/u/sites/gems/gemupdate.sh'`
 end
 
 desc "Publish the API documentation"
 task :pdoc => [:rdoc] do 
+  require 'rake/contrib/sshpublisher'
   Rake::SshDirPublisher.new("wrath.rubyonrails.org", "public_html/as", "doc").upload
 end