Fix for #2644 - Specified Nonce isn't used

Added nonceSpecified.
And a check if nonce was specified - then we should use the specified nonce instead of generating a new one.

app/scripts/controllers/transactions.js

@@ -177,6 +177,7 @@ module.exports = class TransactionController extends EventEmitter {
     const txParams = txMeta.txParams
     // ensure value
     txMeta.gasPriceSpecified = Boolean(txParams.gasPrice)
+    txMeta.nonceSpecified = Boolean(txParams.nonce)
     const gasPrice = txParams.gasPrice || await this.query.gasPrice()
     txParams.gasPrice = ethUtil.addHexPrefix(gasPrice.toString(16))
     txParams.value = txParams.value || '0x0'
@@ -200,7 +201,11 @@ module.exports = class TransactionController extends EventEmitter {
       // wait for a nonce
       nonceLock = await this.nonceTracker.getNonceLock(fromAddress)
       // add nonce to txParams
+      if (txMeta.nonceSpecified) {
+        txMeta.txParams.nonce = ethUtil.addHexPrefix(txMeta.txParams.nonce.toString(16))
+      } else {
         txMeta.txParams.nonce = ethUtil.addHexPrefix(nonceLock.nextNonce.toString(16))
+      }
       // add nonce debugging information to txMeta
       txMeta.nonceDetails = nonceLock.nonceDetails
       this.txStateManager.updateTx(txMeta, 'transactions#approveTransaction')