iface-modem-[3gpp|cdma]: remove contexts with timeouts when shutting down

Following the same logic as in commit 9ddcf92a, those contexts in the interface
which contain the setup of a timeout are cleared before removing the DBus
skeleton objects, so that we make sure they are not fired out once these have
been disposed.

src/mm-iface-modem-3gpp.c

@@ -1868,6 +1868,14 @@ mm_iface_modem_3gpp_shutdown (MMIfaceModem3gpp *self)
 {
     g_return_if_fail (MM_IS_IFACE_MODEM_3GPP (self));
 
+    /* Remove RegistrationCheckContext object to make sure any pending
+     * invocation of periodic_registration_check is cancelled before the
+     * DBus skeleton is removed. */
+    if (G_LIKELY (registration_check_context_quark))
+        g_object_set_qdata (G_OBJECT (self),
+                            registration_check_context_quark,
+                            NULL);
+
     /* Unexport DBus interface and remove the skeleton */
     mm_gdbus_object_skeleton_set_modem3gpp (MM_GDBUS_OBJECT_SKELETON (self), NULL);
     g_object_set (self,

src/mm-iface-modem-cdma.c

@@ -1551,6 +1551,14 @@ mm_iface_modem_cdma_shutdown (MMIfaceModemCdma *self)
 {
     g_return_if_fail (MM_IS_IFACE_MODEM_CDMA (self));
 
+    /* Remove RegistrationCheckContext object to make sure any pending
+     * invocation of periodic_registration_check is cancelled before the
+     * DBus skeleton is removed. */
+    if (G_LIKELY (registration_check_context_quark))
+        g_object_set_qdata (G_OBJECT (self),
+                            registration_check_context_quark,
+                            NULL);
+
     /* Unexport DBus interface and remove the skeleton */
     mm_gdbus_object_skeleton_set_modem_cdma (MM_GDBUS_OBJECT_SKELETON (self), NULL);
     g_object_set (self,