Webserver fails to display device manager when RUNMODE set to dummy

[vid553]

Hi,
I wanted to use horizon GUI on my PC but it failed to display the device manager page.

Setup:

• Ubuntu 18.04.4 LTS
• installation done according to stage 2 of the readme file
• changed RUNMODE to dummy in constants.py

Webserver failed to display the page (code 500) when Device Manager link or Device Scan button had been pressed.

I traced the error to the following line: https://github.com/arribada/horizon-gui/blob/master/webserver/hardwareVersion/v4.0/deviceFunctions.py#L122

Solution:
Changed that line to: return dummyResponses['SCAN']