connman integration issue after recent updates

Hi Guix,

I'm using `connman` + `cmst` for network management on my guix machine, recently after I updated the system, I receive following message after login and `cmst` can't communicate with `connman`. I also tried with `econnman` interface and received same error:

```

Error Name: org.freedesktop.DBus.Error.AccessDenied

Error Message: Rejected send message, 3 matched rules; type="method_call", sender=":1.108" (uid=1000 pid=3870 comm="cmst ") interface="net.connman.Manager" member="GetTechnologies" error name="(unset)" requested_reply="0" destination="net.connman" (uid=0 pid=369 comm="/gnu/store/1ld7hpvnhcr5wjxd15bvgbwvd50j8i04-connma")

```

I also tried to modify `connman` package and add

<allow send_interface="net.connman.Manager"/>

policy to connman debus config, based on suggested details in:

but the problem still occurs.

--

Regards

Reza Alizadeh Majd

PantherX Team

here is a sample configuration file that I used to reproduce the issue:

(use-modules (gnu)

(gnu system nss)

(gnu packages gnome)

(gnu packages vim)

(srfi srfi-1))

(use-service-modules desktop networking ssh xorg)

(use-package-modules screen ssh certs tls connman)

(operating-system

(host-name "panther")

(timezone "Asia/Tehran")

(locale "en_US.utf8")

;; Boot in "legacy" BIOS mode

(bootloader (bootloader-configuration

(bootloader grub-bootloader)

(target "/dev/sda")))

(file-systems (cons (file-system

(device (file-system-label "my-root"))

(mount-point "/")

(type "ext4"))

%base-file-systems))

(users (cons (user-account

(name "user")

(comment "default user")

(group "users")

(supplementary-groups '("wheel" "audio" "video"))

(home-directory "/home/user"))

%base-user-accounts))

(packages (cons* openssh nss-certs gnutls cmst

%base-packages))

(services (cons* (service gnome-desktop-service-type)

(service openssh-service-type

(openssh-configuration

(port-number 22)

(permit-root-login #t)

(authorized-keys

`(("user" ,(local-file "/etc/vagrant.pub"))

("root" ,(local-file "/etc/vagrant.pub"))))))

(service connman-service-type)

(remove (lambda (service)

(eq? (service-kind service) network-manager-service-type))

%desktop-services)))

(name-service-switch %mdns-host-lookup-nss))

--

Regards

Reza Alizadeh Majd

PantherX Team