Update gitignore to exclude test Dockerfiles
Update gitignore to exclude test Dockerfiles

Signed-off-by: Brandon Lum <3f6482c5eb7fd38182f7c556102c9a320d585f85@gmail.com>

rhatdan/buildah,rhatdan/buildah,rhatdan/buildah,nalind/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,nalind/buildah,nalind/buildah-1,nalind/buildah-1,projectatomic/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,TomSweeneyRedHat/buildah,nalind/buildah-1