esp8266/modules/webrepl_setup: Fix first-time enable of WebREPL.
esp8266/modules/webrepl_setup: Fix first-time enable of WebREPL.

Prior to this fix, enabling WebREPL for the first time via webrepl_setup
did not work at all because "boot.py" did not contain any lines with
"webrepl" in them that could be uncommented.

bvernoux/micropython,tralamazza/micropython,pfalcon/micropython,kerneltask/micropython,pramasoul/micropython,pozetroninc/micropython,blazewicz/micropython,ryannathans/micropython,tralamazza/micropython,pramasoul/micropython,tobbad/micropython,MrSurly/micropython,infinnovation/micropython,ryannathans/micropython,blazewicz/micropython,MrSurly/micropython,tralamazza/micropython,kerneltask/micropython,henriknelson/micropython,pramasoul/micropython,lowRISC/micropython,tralamazza/micropython,pfalcon/micropython,bvernoux/micropython,dmazzella/micropython,pozetroninc/micropython,swegener/micropython,trezor/micropython,adafruit/circuitpython,ryannathans/micropython,adafruit/micropython,pozetroninc/micropython,adafruit/micropython,pramasoul/micropython,lowRISC/micropython,swegener/micropython,infinnovation/micropython,henriknelson/micropython,tobbad/micropython,MrSurly/micropython,infinnovation/micropython,selste/micropython,blazewicz/micropython,henriknelson/micropython,infinnovation/micropython,MrSurly/micropython,ryannathans/micropython,bvernoux/micropython,lowRISC/micropython,adafruit/circuitpython,kerneltask/micropython,ryannathans/micropython,lowRISC/micropython,pfalcon/micropython,kerneltask/micropython,pfalcon/micropython,selste/micropython,swegener/micropython,tobbad/micropython,adafruit/circuitpython,MrSurly/micropython,trezor/micropython,kerneltask/micropython,blazewicz/micropython,dmazzella/micropython,selste/micropython,trezor/micropython,dmazzella/micropython,selste/micropython,pozetroninc/micropython,trezor/micropython,pfalcon/micropython,tobbad/micropython,dmazzella/micropython,selste/micropython,adafruit/circuitpython,bvernoux/micropython,lowRISC/micropython,adafruit/circuitpython,infinnovation/micropython,adafruit/micropython,pozetroninc/micropython,trezor/micropython,adafruit/micropython,pramasoul/micropython,adafruit/micropython,swegener/micropython,henriknelson/micropython,blazewicz/micropython,tobbad/micropython,henriknelson/micropython,bvernoux/micropython,swegener/micropython,adafruit/circuitpython