Fully qualify vendored ninja
Fully qualify vendored ninja

Though our tap will be tapped when we run this script (by definition!)
it may not be pinned. As we now install our vendored ninja, fully
qualify its name to avoid a clash with upstream.

SuperNEMO-DBD/homebrew-cadfael,SuperNEMO-DBD/homebrew-cadfael,xgarrido/homebrew-cadfael,xgarrido/homebrew-cadfael