fixed rspec dependency issue

git-svn-id: https://dev.finn.de/svn/cockpit/trunk@215 7926756e-e54e-46e6-9721-ed318f58905e

tasks/spec.rake

@@ -1,6 +1,6 @@
-require "spec/rake/spectask"
-
-namespace :spec do
+begin
+  require "spec/rake/spectask"
+  namespace :spec do
     namespace :plugins do
       desc "Runs the examples for redmine_costs"
       Spec::Rake::SpecTask.new(:redmine_costs) do |t|
@@ -8,6 +8,7 @@ namespace :spec do
         t.spec_files = FileList['vendor/plugins/redmine_costs/spec/**/*_spec.rb']
       end
     end
+  end
+  task :spec => "spec:plugins:redmine_costs"
+rescue LoadError
 end
-
-task :spec => "spec:plugins:redmine_costs"