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]

I'm sorry to heard that ,Take care of yourself! Wish you recover soon!the sdk version is 10.0.0,THX