For giveownership to new members, give old owner access 499 instead of 400.

For giveownership to new members, give old owner access 499 instead of 400.

src/chanserv.c (cmd_giveownership): When the new user did not exist, give
  them UL_OWNER-1 (499) access rather than UL_COOWNER, so that when the
  access levels are swapped later, the previous owner ends up with 499.