the digest engine failed to support openssl soft work.

[docularxu]

Digest engine cannot support OpenSSL soft method. Previous tests with Nginx return error.

Reference:
commit id：642f818777f7f9d1e20571113c0a36d9dee83724
digest:
add openssl soft work supporting for digest engine

1. Fix me: Use the soft working when the input value is lower than
   threshold. this feature cause the nginx error.

2. Use the soft working when the hardware error is happened.

3. Modify the function name in order to make a distinction.

Signed-off-by: Kai Ye yekai13@huawei.com

Kai Ye: 可能是软算释放的时候会有问题。没有继续跟进。