add a colon to the mock Procfile

spec/spec_helper.rb

@@ -27,7 +27,7 @@ end
 def write_procfile(procfile="Procfile")
   File.open(procfile, "w") do |file|
     file.puts "alpha ./alpha"
-    file.puts "bravo ./bravo"
+    file.puts "bravo: ./bravo"
   end
 end