add 'env' and 'passenv' service parameters

from man xinetd.conf:

       env              The  value of this attribute is a list of strings of the form ’name=value’.  These strings will be added to the environment before starting a server (therefore the server’s envi-
                        ronment will include xinetd’s environment plus the specified strings).

       passenv          The value of this attribute is a list of environment variables from xinetd’s environment that will be passed to the server.  An empty list implies passing  no  variables  to  the
                        server  except  for those explicitly defined using the env attribute.  (notice that you can use this attribute in conjunction with the env attribute to specify exactly what envi-
                        ronment will be passed to the server).