connman: correct the systemd boot in read only rootfs

connman: correct the systemd boot in read only rootfs

connman fails to start in systemd based read-only images while creating links:

Jun 08 12:53:56 qemux86-64 systemd[1]: Starting Create Volatile Files
and Directories...
Jun 08 12:53:56 qemux86-64 systemd-tmpfiles[366]:
[[0;1;31msymlink(/var/run/connman/resolv.conf, /etc/resolv.conf) failed:
Read-only file system[[0m

Fix this failure and make connman co-exist with systemd-resolved.

Signed-off-by: Maxin B. John <maxin.john@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>