Fixed deadlock in CRYPTO_THREAD_run_once for Windows

Fixed deadlock in CRYPTO_THREAD_run_once() if call to init() is causing
a recursive call to CRYPTO_THREAD_run_once() again that is causing a hot
deadloop inside do { } while (result == ONCE_ININIT); section.

CLA: trivial
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1913)