Add /snap/bin in case it is missing

This is a fix to bug 863
https://osm.etsi.org/bugzilla/show_bug.cgi?id=863



Change-Id: Iccbe1de7ca4a36960f450de918fcad67364b7d3d
Signed-off-by: Dominik Fleischmann <dominik.fleischmann@canonical.com>