[frontend] Fix file details link for multibuild packages

With 9347214 the binary view got fixed
for multibuild packages by using the using the package (multibuild) name
instead of the package container.

While this fixed the binary view, some of the page that got linked from
there were still not handling multibuild packages.
This commit is fixing the file details link.

src/api/app/controllers/webui/package_controller.rb

@@ -147,7 +147,7 @@ def binary
     @filename = File.basename(params[:filename])
 
     begin
-      @fileinfo = Fileinfo.find(project: @project, package: @package, repository: @repository, arch: @arch,
+      @fileinfo = Fileinfo.find(project: @project, package: params[:package], repository: @repository, arch: @arch,
         filename: @filename, view: 'fileinfo_ext')
     rescue ActiveXML::Transport::ForbiddenError, ActiveXML::Transport::Error => e
       flash[:error] = "File #{@filename} can not be downloaded from #{@project}: #{e.summary}"