tp_account_manager_is_prepared: fix a confusing typo
tp_account_manager_is_prepared: fix a confusing typo

TP_ACCOUNT_MANAGER_FEATURE_CORE, not TP_ACCOUNT_FEATURE_CORE.

Reviewed-by: Will Thompson <5822fdda638242a44ccfa68f146ccf6f257c5cbd@collabora.co.uk>

Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib