Merge pull request #1500 from dexidp/sr/fix-some-lint-issues

cmd/dex/serve.go

connector/github/github.go

connector/gitlab/gitlab_test.go

connector/keystone/keystone.go

connector/oidc/oidc.go

connector/saml/saml.go

connector/saml/saml_test.go

server/oauth2.go

server/rotation.go

server/server.go

server/server_test.go

storage/etcd/types.go

storage/sql/config.go