Traces error handling (#4849)

ethcore/src/client/error.rs

@@ -14,7 +14,6 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-use trace::Error as TraceError;
 use util::UtilError;
 use std::fmt::{Display, Formatter, Error as FmtError};
 
@@ -23,8 +22,6 @@ use util::trie::TrieError;
 /// Client configuration errors.
 #[derive(Debug)]
 pub enum Error {
-	/// TraceDB configuration error.
-	Trace(TraceError),
 	/// TrieDB-related error.
 	Trie(TrieError),
 	/// Database error
@@ -33,12 +30,6 @@ pub enum Error {
 	Util(UtilError),
 }
 
-impl From<TraceError> for Error {
-	fn from(err: TraceError) -> Self {
-		Error::Trace(err)
-	}
-}
-
 impl From<TrieError> for Error {
 	fn from(err: TrieError) -> Self {
 		Error::Trie(err)
@@ -60,7 +51,6 @@ impl<E> From<Box<E>> for Error where Error: From<E> {
 impl Display for Error {
 	fn fmt(&self, f: &mut Formatter) -> Result<(), FmtError> {
 		match *self {
-			Error::Trace(ref err) => write!(f, "{}", err),
 			Error::Trie(ref err) => write!(f, "{}", err),
 			Error::Util(ref err) => write!(f, "{}", err),
 			Error::Database(ref s) => write!(f, "Database error: {}", s),