util: Don't reference errno when pthread fails.
util: Don't reference errno when pthread fails.

Pthread library does not set errno.
Pthread library's errno is returned by return value.

Co-authored-by: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>

Former-commit-id: 7ec05891ba34b1adaf2605f09f4b316034db6d18
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin