validation: make `line-directive` python 3.5 friendly
validation: make `line-directive` python 3.5 friendly

`ModuleNotFoundError` was introduced in python 3.6 as a child of
`ImportError`.  However, some of the CI hosts use python 3.5.  Use
`ImportError` as the filter type to be compatible with earlier python
versions.

allevato/swift,jckarter/swift,jckarter/swift,benlangmuir/swift,nathawes/swift,rudkx/swift,airspeedswift/swift,apple/swift,benlangmuir/swift,hooman/swift,glessard/swift,xwu/swift,JGiola/swift,ahoppen/swift,hooman/swift,glessard/swift,xwu/swift,airspeedswift/swift,benlangmuir/swift,atrick/swift,atrick/swift,parkera/swift,parkera/swift,jmgc/swift,allevato/swift,allevato/swift,nathawes/swift,parkera/swift,jmgc/swift,tkremenek/swift,rudkx/swift,JGiola/swift,ahoppen/swift,JGiola/swift,ahoppen/swift,roambotics/swift,xwu/swift,CodaFi/swift,CodaFi/swift,CodaFi/swift,hooman/swift,tkremenek/swift,glessard/swift,rudkx/swift,airspeedswift/swift,airspeedswift/swift,parkera/swift,gregomni/swift,jmgc/swift,hooman/swift,JGiola/swift,gregomni/swift,tkremenek/swift,nathawes/swift,hooman/swift,CodaFi/swift,allevato/swift,xwu/swift,tkremenek/swift,allevato/swift,nathawes/swift,jmgc/swift,airspeedswift/swift,benlangmuir/swift,xwu/swift,airspeedswift/swift,glessard/swift,xwu/swift,allevato/swift,apple/swift,xwu/swift,ahoppen/swift,parkera/swift,rudkx/swift,hooman/swift,CodaFi/swift,jckarter/swift,roambotics/swift,tkremenek/swift,atrick/swift,nathawes/swift,jmgc/swift,apple/swift,ahoppen/swift,parkera/swift,nathawes/swift,rudkx/swift,roambotics/swift,atrick/swift,gregomni/swift,gregomni/swift,parkera/swift,JGiola/swift,benlangmuir/swift,hooman/swift,roambotics/swift,apple/swift,jmgc/swift,atrick/swift,jmgc/swift,apple/swift,benlangmuir/swift,gregomni/swift,parkera/swift,jckarter/swift,airspeedswift/swift,roambotics/swift,jckarter/swift,roambotics/swift,tkremenek/swift,ahoppen/swift,allevato/swift,atrick/swift,nathawes/swift,CodaFi/swift,jckarter/swift,tkremenek/swift,gregomni/swift,jckarter/swift,glessard/swift,glessard/swift,rudkx/swift,CodaFi/swift,JGiola/swift,apple/swift