Baud rate changes cause oddly timed injection of null character

[qdot]

From email from Jason Ekstrand:

I noticed that when you change the baudrate on the FTDI chip, about 50% of the time, it will leave you with a stray null character in the output buffer. My solution to this was to change the baudrate, wait a few milliseconds, and flush the buffer. After accounting for this stray null character, I discovered that the string returned by the falcon in the "Firmware Reset" stage is actually "\x0a\x44\x2c\x0d", not "\x00\x0a\x44\x2c\x0d".