when gnome-3.14 starts after signing in from gdm, gnome crashes and I was returned to gdm login screen. logs show GLib-GIO-ERROR: Settings schema 'org.gnome.Vino' does not contain a key named 'enabled' after manually rm /etc/xdg/autostart/vino-server.desktop gnome starts properly. This file is left from 3.12 and should be removed when 3.14.1 is installed or it will cause problem.
Most likely you edited this file manually thus package manager skipped it on unmerging of old files.
I don't think so but in any case it would be a good idea for vino-3.14 ebuild to check for the file and delete it if it is there because it causes gnome-session to crash on startup and will likely be a support headache
I confirm this, and I have never touched this file.
*gnome-session-3.14.0-r1 (18 Jan 2015) 18 Jan 2015; Pacho Ramos <pacho@gentoo.org> +files/defaults.list-r3, +files/gnome-session-3.14.0-validate-autostart.patch, +gnome-session-3.14.0-r1.ebuild: Patch from 3.14 branch to fix crash when autostart conditions are wrong, use new location for defaults list (#534790), update that list to fit new names for .desktop files in 3.14 cycle. That upstream commit is for fixing this concrete case: https://bugzilla.gnome.org/show_bug.cgi?id=740119