Remove VumiService wrapper since vumi workers are now themselves already services.
Remove VumiService wrapper since vumi workers are now themselves already services.

vishwaprakashmishra/xmatrix,TouK/vumi,vishwaprakashmishra/xmatrix,vishwaprakashmishra/xmatrix,harrissoerja/vumi,TouK/vumi,harrissoerja/vumi,harrissoerja/vumi,TouK/vumi