set static pass key for nrf51822 in example code--hrs with dfu ，nrf51822 reboot

[RiverYWang]

we add static pass key in example code hrs with dfu，but when connecting with phone，input passkey on phone，the nrf51822 will rebootdevice_manager_cnfg.h main.c

[RiverYWang]

we still have this problem, we try to use whitelist to solve it. maybe you can provide about whitelist information for us? thanks a lot!!