recovery-flash: don't try to flash non-existent vector.img
recovery-flash: don't try to flash non-existent vector.img

vector.img do not exist. Don't try to fastboot flash it.
Otherwise we see following non-fatal fastboot failure in
host machine log:

error: cannot load '.../tools-images-hikey960/vector.img': No such file or directory

Signed-off-by: Amit Pundir <a4a7d486fe874593b021ebde938f459c081be043@linaro.org>

96boards-hikey/tools-images-hikey960,96boards-hikey/tools-images-hikey960