Fix user-guide/skeleton-application.rst broken links

Fix broken links as seen in ```make linkcheck``` output:

>user-guide/skeleton-application.rst:114: [broken] http://zf2-tutorial.localhost: <urlopen error [Errno -2] Name or service not known>
user-guide/skeleton-application.rst:84: [broken] http://zf2-tutorial.localhost: <urlopen error [Errno -2] Name or service not known>
user-guide/skeleton-application.rst:130: [broken] http://zf2-tutorial.localhost/1234: <urlopen error [Errno -2] Name or service not known>