attempt to get around rake 10.0.3 issue with ruby 1.9.2

see jimweirich/rake#157

Rakefile

@@ -12,14 +12,17 @@ task :spec do
     Rake::Task["#{adapter}:spec"].invoke
 end
 
-require 'rdoc/task'
-Rake::RDocTask.new do |rdoc|
-  require File.dirname(__FILE__) + '/lib/schema_plus/version'
+# work around a bug in rake 10.0.3 with ruby 1.9.2
+unless RUBY_VERSION == "1.9.2"
+    require 'rdoc/task'
+    Rake::RDocTask.new do |rdoc|
+    require File.dirname(__FILE__) + '/lib/schema_plus/version'
 
-  rdoc.rdoc_dir = 'rdoc'
-  rdoc.title = "schema_plus #{SchemaPlus::VERSION}"
-  rdoc.rdoc_files.include('README*')
-  rdoc.rdoc_files.include('lib/**/*.rb')
+    rdoc.rdoc_dir = 'rdoc'
+    rdoc.title = "schema_plus #{SchemaPlus::VERSION}"
+    rdoc.rdoc_files.include('README*')
+    rdoc.rdoc_files.include('lib/**/*.rb')
+    end
 end
 
 require 'rspec/core/rake_task'