@DELETE
  @Path("{userName}")
  @Produces("text/plain")
  @ApiOperation(value = "Delete single user")
  @ApiResponses(value = {
      @ApiResponse(code = 200, message = "Successful operation"),
      @ApiResponse(code = 500, message = "Server Error")}
  )
  public Response deleteUser(@Context HttpHeaders headers, @Context UriInfo ui,
                             @ApiParam(value = "user name", required = true) @PathParam("userName") String userName) {
    return handleRequest(headers, null, ui, Request.Type.DELETE, createUserResource(userName));
  }
Deletes a user.
Handles:  DELETE /users/{userName}
ambari-server/src/main/java/org/apache/ambari/server/api/services/users/UserService.java