facebook: fix boolean expression
facebook: fix boolean expression

In general, "!a == b" is not the same as "a != b". In this case,
JSON_NODE_OBJECT equals 0, so it happened to work fine.

The data comes from an external source so it is not trusted.

lcp/libsocialweb,GNOME/libsocialweb,ThomasBollmeier/libsocialweb-flickr-oauth,ThomasBollmeier/libsocialweb-flickr-oauth,ThomasBollmeier/libsocialweb-flickr-oauth,lcp/libsocialweb,GNOME/libsocialweb,GNOME/libsocialweb,lcp/libsocialweb