procd: fix service file tracking

The instance_config_move() function in the procd instance managing code is
missing a blobmsg_list_move() call to update the tracked file items with the
newly calculated checksums in case of a file change.

Without that change, services are always reloaded after the first change to
a tracked file regardless of whether there are any subsequent changes or not.

Add a missing instance of blobmsg_list_free() as well.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

SVN-Revision: 39132