[webui][api] Fix exception raising in ChannelTarget method

src/api/app/models/channel_target.rb

@@ -24,7 +24,7 @@ def self.find_by_repo(repo, projectFilter = nil)
       ct.each do |cti|
         msg << "#{cti.channel.package.project.name}/#{cti.channel.package.name}, "
       end
-      raise MultipleChannelTargets "Multiple channel targets found in #{msg} for repository #{repo.project.name}/#{repo.name}"
+      raise MultipleChannelTargets, "Multiple channel targets found in #{msg} for repository #{repo.project.name}/#{repo.name}"
     end
     return ct.first
   end