external: leaflet.draw-src.js: workaround for Leaflet/Leaflet.draw#789 …

…(Can only draw two-point polygons in Chrome w/ Touch)

Although the source of the issue is somewhere deeper, it seems that just
commenting out these 2 lines is enough to solve it.

I observe no functionality loss with this change, perhaps the code was redundant
for some unclear reason.

Adapted from Leaflet/Leaflet.draw#926