Bug #3143: Take into account that not all PUBLIC_CLOUD sections are SoftLayer's

(cherry picked from commit ac9a4430beefb95c4d0521cae666d33ef2f69d0c)
Bug #3145: Pick the right instance type when multiple PUBLIC_CLOUDS sections are defined

(cherry picked from commit c01a220d11a6ac7d7afae2a410a1f1ef61b6cce8)