Fix a function clause in mod_roster_odbc:fill_subscription_lists.

Before:
```
{<<"to">>, jlib:jid_to_binary(LServer)} %% typo error?
```
After:
```
{<<"to">>, jlib:jid_to_binary(JID)}
```
Old code cause an function clause error, because `LServer` is not a JID, but a host name.