Add missing feature guard on macro_use
This change adds a cfg_attr guard to macro_use for diesel_macros, to
correct a clippy warning.
@@ -22,7 +22,7 @@ extern crate log;
#[cfg_attr(feature = "commit-store", macro_use)]
extern crate diesel;
#[cfg(feature = "diesel_migrations")]
-#[macro_use]
+#[cfg_attr(feature = "commit-store", macro_use)]
extern crate diesel_migrations;
#[macro_use]
extern crate serde_derive;
