Code changed in jenkins
User: Andrew Bayer
[FIXED JENKINS-38169] Treat single required+named param differently.
If you call `echo message:'foo'` previous to this change, the Map that
gets passed as the first element of args ends up being used as the
sole parameter itself, so you end up with `name:[name:'foo']` being
passed as the args. That's obviously wrong. So let's add a check to
see if there is a `soleArgumentKey`, the arg map only has one
key/value, and that key is equal to `soleArgumentKey` - if that's
true, just pass the arg map directly.