Fix Burn Bootloader SAMD.

[chocotov1]

When trying to burn the bootloader of my samd board the following openocd error would appear:

Error: couldn't open {/home/chocotov1/Arduino/hardware/sparkfun/samd/bootloaders/zero/Sparkfun_SAMD21_ProRF.bin}

The openocd command that was executed as seen in the console:

home/chocotov1/.arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/bin/openocd -d2 -s /home/chocotov1/.arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/share/openocd/scripts/ -f /home/chocotov1/Arduino/hardware/sparkfun/samd/variants/SparkFun_ProRF/openocd_scripts/arduino_zero.cfg -c telnet_port disabled; init; halt; at91samd bootloader 0; program {{/home/chocotov1/Arduino/hardware/sparkfun/samd/bootloaders/zero/Sparkfun_SAMD21_ProRF.bin}} verify reset; shutdown

[chocotov1]

The changed line 186 solved my problem. Since line 213 looks so similar I changed it there too.