The LaunchD Disabled key is now not changed in the launchD item, but a plist is kept that overrides the settings
on 10.9 and 10.10 it works like this :-
launchctl load -w modifies /var/db/launchd.db/com.apple.launchd.peruser.501/overrides.plist where 501 is the UID of the user running launchctl
sudo launchctl load -w modifies /var/db/launchd.db/com.apple.launchd/overrides.plist and overrides individuals settings
On 10.11 the path is slightly different
/var/db/com.apple.xpc.launchd