be_false is deprecated

Use `be false` (for exact `== false` equality) instead.

spec/oauth2/client_spec.rb

@@ -58,7 +58,7 @@
 
     it "allows true/false for raise_errors option" do
       client = OAuth2::Client.new('abc', 'def', :site => 'https://api.example.com', :raise_errors => false)
-      expect(client.options[:raise_errors]).to be_false
+      expect(client.options[:raise_errors]).to be false
       client = OAuth2::Client.new('abc', 'def', :site => 'https://api.example.com', :raise_errors => true)
       expect(client.options[:raise_errors]).to be true
     end