Correct parameters for eth_sign (#2703)

* Cherry-pick eth_sign update/fix

* Correct sign documentation (signs txhash)

js/src/api/format/input.js

@@ -46,6 +46,10 @@ export function inData (data) {
   return inHex(data);
 }
 
+export function inHash (hash) {
+  return inHex(hash);
+}
+
 export function inTopics (_topics) {
   let topics = (_topics || [])
     .filter((topic) => topic)

js/src/api/rpc/eth/eth.js

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-import { inAddress, inBlockNumber, inData, inFilter, inHex, inNumber16, inOptions } from '../../format/input';
+import { inAddress, inBlockNumber, inData, inFilter, inHash, inHex, inNumber16, inOptions } from '../../format/input';
 import { outAddress, outBlock, outLog, outNumber, outReceipt, outTransaction } from '../../format/output';
 
 export default class Eth {
@@ -292,9 +292,9 @@ export default class Eth {
       .execute('eth_sendTransaction', inOptions(options));
   }
 
-  sign () {
+  sign (address, hash) {
     return this._transport
-      .execute('eth_sign');
+      .execute('eth_sign', inAddress(address), inHash(hash));
   }
 
   signTransaction () {

js/src/jsonrpc/interfaces/eth.js

@@ -924,7 +924,7 @@ export default {
   },
 
   sign: {
-    desc: 'Signs data with a given address.\n**Note** the address to sign must be unlocked.',
+    desc: 'Signs transaction hash with a given address.',
     params: [
       {
         type: Address,
@@ -933,7 +933,7 @@ export default {
       },
       {
         type: Data,
-        desc: 'Data to sign'
+        desc: 'Transaction hash to sign'
       }
     ],
     returns: {