fix ASSERT in _get_block_timestamp.
fix ASSERT in _get_block_timestamp.

If the block we're looking up in not in hash_blk, it may be in hash_orphans.

dxtr/bitc,repos-bitcoin/bitc,repos-bitcoin/bitc,jma127/bitc-rpc,jma127/bitc-rpc,bit-c/bitc,dxtr/bitc,jma127/bitc-rpc,bit-c/bitc,bit-c/bitc,Methimpact/bitc,Methimpact/bitc,Methimpact/bitc,repos-bitcoin/bitc,dxtr/bitc