removed deprecated commented fifo config names to avoid confusion

etc/ser.cfg

@@ -41,9 +41,6 @@ rev_dns=no      # (cmd. line: -R)
 #children=4
 #user=ser
 #group=ser
-#fifo_user=ser # owner of the ser fifo
-#fifo_group=ser
-#fifo_mode=0660 # fifo's permissions
 #disable_core=yes #disables core dumping
 #open_fd_limit=1024 # sets the open file descriptors limit
 #mhomed=yes  # usefull for multihomed hosts, small performance penalty