74e2dbd JNI: fix use sig array (liuyujun)
Pull request description:
ACKs for commit 74e2db:
sipa:
ACK 74e2dbd68e. This is clearly an improvement.
real-or-random:
ACK 74e2dbd68e I've read the code but haven't tested it
Tree-SHA512: 850b32e893463be4be28185dcc127d429afe4b6076036a078b7c61d590e0f4ea89127e448760b71c087cf70ffbefc52d87db77a5131bee81f3e4f95cfbd3bd3e