catch newline issues in xinet.d (#2043)

The fix is already provided here: https://github.com/chef/inspec/pull/2040

This PR only adds a unit test to catch it

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>

test/unit/mock/files/xinetd.d_chargen-dgram

@@ -8,4 +8,4 @@ service chargen
     socket_type	= dgram
     # How protocol is defined by default in CentOS 6:
     # protocol	=  socket type is usually enough
-}
+}