Allow deprecated hash syntax in Cask headers

Library/Homebrew/cask/lib/hbc/source/path_base.rb

@@ -55,6 +55,10 @@ class Hbc::Source::PathBase
   end
 
   def build_cask(cask_class, header_token, &block)
+    if header_token.is_a?(Hash)
+      # Cask file is using old `cask :v1 => 'token'` syntax
+      header_token = header_token.values.first
+    end
     raise Hbc::CaskTokenDoesNotMatchError.new(cask_token, header_token) unless cask_token == header_token
     cask_class.new(cask_token, sourcefile_path: path, &block)
   end

Library/Homebrew/cask/test/cask/dsl_test.rb

@@ -62,6 +62,15 @@ describe Hbc::DSL do
 
     it "does not require a DSL version in the header" do
       test_cask = Hbc.load("no-dsl-version")
+      test_cask.token.must_equal "no-dsl-version"
+      test_cask.url.to_s.must_equal "http://example.com/TestCask.dmg"
+      test_cask.homepage.must_equal "http://example.com/"
+      test_cask.version.to_s.must_equal "1.2.3"
+    end
+
+    it "may use deprecated DSL version hash syntax" do
+      test_cask = Hbc.load("with-dsl-version")
+      test_cask.token.must_equal "with-dsl-version"
       test_cask.url.to_s.must_equal "http://example.com/TestCask.dmg"
       test_cask.homepage.must_equal "http://example.com/"
       test_cask.version.to_s.must_equal "1.2.3"

Library/Homebrew/cask/test/support/Casks/with-dsl-version.rb

+test_cask :v1 => 'with-dsl-version' do
+  version '1.2.3'
+  sha256 '8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b'
+
+  url 'http://example.com/TestCask.dmg'
+  homepage 'http://example.com/'
+
+  app 'TestCask.app'
+end