Fix some clippy warnings

src/error.rs

@@ -8,7 +8,7 @@ use std::str;
 
 /// Enum listing possible errors from rusqlite.
 #[derive(Debug)]
-#[allow(enum_variant_names)]
+#[allow(clippy::enum_variant_names)]
 pub enum Error {
     /// An error from an underlying SQLite call.
     SqliteFailure(ffi::Error, Option<String>),

src/row.rs

@@ -27,7 +27,7 @@ impl<'stmt> Rows<'stmt> {
     /// This is a "streaming iterator". For a more natural interface,
     /// consider using `query_map` or `query_and_then` instead, which
     /// return types that implement `Iterator`.
-    #[cfg_attr(feature = "cargo-clippy", allow(should_implement_trait))] // cannot implement Iterator
+    #[allow(clippy::should_implement_trait)] // cannot implement Iterator
     pub fn next<'a>(&'a mut self) -> Option<Result<Row<'a, 'stmt>>> {
         self.stmt.and_then(|stmt| match stmt.step() {
             Ok(true) => Some(Ok(Row {

src/types/from_sql.rs

@@ -47,7 +47,7 @@ impl Error for FromSqlError {
         }
     }
 
-    #[cfg_attr(feature = "clippy", allow(match_same_arms))]
+    #[allow(clippy::match_same_arms)]
     fn cause(&self) -> Option<&Error> {
         match *self {
             FromSqlError::Other(ref err) => err.cause(),