GCancellable: drop lock for callback during connect()
GCancellable: drop lock for callback during connect()

Don't hold the lock when calling the user's callback during
g_cancellable_connect() for the case that the cancellable has already
fired.

Taken from a patch by Alex Larsson.

Doc updates from Colin Walters.

https://bugzilla.gnome.org/show_bug.cgi?id=705395

MathieuDuponchelle/glib,johne53/MB3Glib,krichter722/glib,krichter722/glib,endlessm/glib,cention-sany/glib,mzabaluev/glib,krichter722/glib,MathieuDuponchelle/glib,johne53/MB3Glib,tchakabam/glib,gale320/glib,tchakabam/glib,endlessm/glib,johne53/MB3Glib,ieei/glib,lukasz-skalski/glib,tchakabam/glib,johne53/MB3Glib,MathieuDuponchelle/glib,mzabaluev/glib,Distrotech/glib,Distrotech/glib,cention-sany/glib,lukasz-skalski/glib,gale320/glib,tamaskenez/glib,mzabaluev/glib,cention-sany/glib,ieei/glib,endlessm/glib,MathieuDuponchelle/glib,endlessm/glib,ieei/glib,lukasz-skalski/glib,gale320/glib,lukasz-skalski/glib,mzabaluev/glib,cention-sany/glib,lukasz-skalski/glib,Distrotech/glib,Distrotech/glib,MathieuDuponchelle/glib,endlessm/glib,krichter722/glib,tchakabam/glib,gale320/glib,tchakabam/glib,tamaskenez/glib,ieei/glib,cention-sany/glib,tamaskenez/glib,tamaskenez/glib,mzabaluev/glib,Distrotech/glib,ieei/glib,tamaskenez/glib,krichter722/glib,johne53/MB3Glib,johne53/MB3Glib,gale320/glib