mantle: fix offline detection in testiso tests

The offline detection in our testiso tests is not working properly
meaning we are never running offline tests today. Let's fix that
here by parsing it properly.

Fixes f98481f.

Author: dustymabe

mantle/cmd/kola/testiso.go

@@ -492,7 +492,10 @@ func runTestIso(cmd *cobra.Command, args []string) error {
 		} else if kola.HasString("uefi", components) {
 			enableUefi = true
 		}
-		if kola.HasString("offline", components) {
+		// For offline it is a part of the first component. i.e. for
+		// iso-offline-install.bios we need to search for 'offline' in
+		// iso-offline-install, which is currently in components[0].
+		if kola.HasString("offline", strings.Split(components[0], "-")) {
 			isOffline = true
 		}