i18n: format_tracking_info "Your branch is behind" message
i18n: format_tracking_info "Your branch is behind" message

Function format_tracking_info in remote.c is called by
wt_status_print_tracking in wt-status.c, which will print
branch tracking message in git-status. git-checkout also
show these messages through it's report_tracking function.

Signed-off-by: Jiang Xin <61b5e6324abee2d58ba2cf49f31c723faf6fd946@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git