dev-install.sh fails when there is a space in the path of python

[mkinney]

Describe the bug If there is a space in the path of python, then the device-install.sh fails at line 49.

To Reproduce Steps to reproduce the behavior:

1. Create a directory with a space in it. "cd /tmp; mkdir a\ b; cd a\ b;"
2. Create python virtual environment. "python3 -m venv venv; source venv/bin/activate; pip install esptool"
3. Change into where the firmware.zip has been unzipped.
4. Run: "./device-install.sh "

Expected behavior Firmware should update.

Screenshots

% ./device-install.sh -f firmware-heltec-v2.1-1.2.51.f9ff06b.bin
Trying to flash firmware-heltec-v2.1-1.2.51.f9ff06b.bin, but first erasing and writing system information
./device-install.sh: line 49: /Users/xxx/ham/meshtastic: is a directory

Device info:

• Device model: HELTEC v2.1
• Software Version: python3
• Firmware: 1.2.51.f9ff06b

Additional context I was able to continue by surrounding the last lines with double quotes:

    "$PYTHON" -m esptool  erase_flash
    "$PYTHON" -m esptool  write_flash 0x1000 system-info.bin
    "$PYTHON" -m esptool  write_flash 0x00390000 spiffs-*.bin
    "$PYTHON" -m esptool  write_flash 0x10000 ${FILENAME}

[mkinney]

User ernax78 pointed out that maybe we should not be determining PYTHON this way:

PYTHON=${PYTHON:-$(which python3 python|head -n 1)}

Perhaps we should use env python3

And, perhaps we should check for esptool availability.