presence-cache: clean up code to replace data form arrays
presence-cache: clean up code to replace data form arrays

This was broken in the case of data_forms == NULL as it left
info->data_forms pointing to a freed GPtrArray. Good catch, Will!

Signed-off-by: Jonny Lamb <3d1fb3642aaab2ff70e3392a5ab916bf99eed6a3@collabora.co.uk>

mlundblad/telepathy-gabble,mlundblad/telepathy-gabble,mlundblad/telepathy-gabble,Ziemin/telepathy-gabble,Ziemin/telepathy-gabble,Ziemin/telepathy-gabble,Ziemin/telepathy-gabble