packer-completion: import from homebrew/completions.

Formula/packer-completion.rb

@@ -0,0 +1,20 @@
+class PackerCompletion < Formula
+  desc "Bash completion for Packer"
+  homepage "https://github.com/mrolli/packer-bash-completion"
+  url "https://github.com/mrolli/packer-bash-completion.git",
+    :revision => "2bd2d9da8bdcc7a763a0c551fa9ae8617dc5ecb7"
+  version "0.6.0"
+
+  head "https://github.com/mrolli/packer-bash-completion.git"
+
+  bottle :unneeded
+
+  def install
+    bash_completion.install "packer"
+  end
+
+  test do
+    assert_match "-F _packer_completion",
+      shell_output("source #{bash_completion}/packer && complete -p packer")
+  end
+end