Update SwmmAlgorithm.py
Created by: sjib
Adapted pathes based on this hint: https://github.com/Oslandia/qgis-swmm/issues/6#issuecomment-112038578
Created by: sjib
Adapted pathes based on this hint: https://github.com/Oslandia/qgis-swmm/issues/6#issuecomment-112038578