ospfd: fix cli shown in running config when turning off ldp-sync

[lynnemorrison]

LDP-Sync is automatically enabled on interfaces when turned on in router ospf context. The user can remove ldp-sync from running on an interface, by issuing a "no ip ospd mpls ldp-sync" command. To remove all ldp-sync interface commands the user must delete ldp-sync at the router level. The code was not correctly removing the config. This PR fixes that issue. Now the extra cli ldp-sync interface commands are removed when ldp-sync is disabled.