greeter:fix bug of 当只有guest和本身账户两个账户时，切换用户会导致两个账户都不会显示，虽然再切换一个就可以显示了
greeter:fix bug of 登陆界面不能用键盘左右键切换用户
greeter:only one switch_userinfo,delete switchtoprev_userinfo and switchtonext_userinfo
desktop.c :g_waring-->g_message
Merge remote-tracking branch 'origin/master' into develop
Merge branch 'develop' of github.com:linuxdeepin/dde into develop