[SourcesManager] Fix the handling of invalid URLs

lib/cocoapods/sources_manager.rb

@@ -423,7 +423,7 @@ module Pod
           host, path = Regexp.last_match.captures
           base = base_from_host_and_path[host, path]
         else
-          url.to_s.downcase
+          base = url.to_s.downcase
         end
 
         name = base

spec/unit/installer/analyzer_spec.rb

@@ -502,7 +502,7 @@ module Pod
             @analyzer.instance_variable_set(:@podfile, podfile)
             should.raise Informative do
               @analyzer.send(:sources)
-            end.message.should.match /not a valid URL/
+            end.message.should.match /Unable to add/
           end
 
           it 'fetches a specs repo that is specified by the podfile' do