Removed search and iterate over each source and corresponding pod_set.

Thanks to @alloy

lib/cocoapods/command/list.rb

@@ -13,7 +13,8 @@ module Pod
       end
 
       def run
-        Source.search_by_name('', false).each do |set|
+        Source.all.each do |source|
+          source.pod_sets.each do |set|
             puts "==> #{set.name} (#{set.versions.reverse.join(", ")})"
             puts "    #{set.specification.summary.strip}"
             puts
@@ -21,4 +22,5 @@ module Pod
         end
       end
     end
+  end
 end