gabble_private_tubes_factory_update_caps: pass value_dup function to tp_g_hash_table_update
gabble_private_tubes_factory_update_caps: pass value_dup function to tp_g_hash_table_update

Features have to be copied as well as hash table assume their are owning them.
Should fix fdo #27131.

community-ssu/telepathy-gabble,community-ssu/telepathy-gabble,community-ssu/telepathy-gabble,community-ssu/telepathy-gabble