Revert "Remove unused branches from Options.coerce"

This reverts commit cee42c339e7632eab15111e2c4e6c121ace6f9e2.

Library/Homebrew/options.rb

@@ -116,6 +116,8 @@ class Options
 
   def self.coerce(arg)
     case arg
+    when self then arg
+    when Option then new << arg
     when Array
       opts = new
       arg.each do |a|

Library/Homebrew/test/test_options.rb

@@ -132,6 +132,15 @@ class OptionsTests < Homebrew::TestCase
     assert_equal [foo, bar, baz].sort, (@options | options).to_a.sort
   end
 
+  def test_coerce_with_options
+    assert_same @options, Options.coerce(@options)
+  end
+
+  def test_coerce_with_option
+    option = Option.new("foo")
+    assert_equal option, Options.coerce(option).to_a.first
+  end
+
   def test_coerce_with_array
     array = %w{--foo --bar}
     option1 = Option.new("foo")