Java kernel v1.5.1 release

This is a recommended update release.

The release mainly fixed a few minor bugs relate with the mining validators, It is highly recommended to update to this version if you have node is running with mining validators.

Bug fixes:

• Fixed createStakingBlockTemplate failed due to the cached parent block data has been overwritten. #1155 #1148
• Fixed redo block import function fail.
• Corrected the mining hash-rate calculation. #1156
• Fixed the incorrect result when querying the pending account nonce.