Incorrect http routes removal

[rosik]

metrics/cartridge/roles/metrics.lua

Lines 45 to 48 in 4a902f5

	local function delete_route(httpd, name)
	httpd.routes[httpd.iroutes[name]] = nil
	httpd.iroutes[name] = nil
	end

This code leaves gaps in httpd.routes table. It may affect other modules. See, for example, fix in Cartridge: tarantool/cartridge#1414