Wrap integration rake in MissingSourceFile rescue to avoid failure when the...

Wrap integration rake in MissingSourceFile rescue to avoid failure when the test gems aren't present.

lib/tasks/integration.rake

@@ -2,6 +2,7 @@
 #   licensed under the Affero General Public License version 3 or later.  See
 #   the COPYRIGHT file.
 
+begin
 namespace :integration do
   desc "rebuild and prepare test db"
   task :gogogo => ['db:integration:prepare', :start_servers, :run_specs]
@@ -46,3 +47,5 @@ namespace :integration do
   end
 
 end
+rescue MissingSourceFile
+end