Increase timeout

Hopefully it will stop the test sporadically failing on Travis CI...

Author: jonleighton

lib/spring/test/acceptance_test.rb

@@ -518,7 +518,7 @@ def exec_name
           assert !spring_env.server_running?
           app.run "spring server &"
 
-          Timeout.timeout(1) do
+          Timeout.timeout(10) do
             sleep 0.1 until spring_env.server_running? && spring_env.socket_path.exist?
           end