Remove a reachable assert from ssl3_write_bytes
Remove a reachable assert from ssl3_write_bytes

A buggy application that call SSL_write with a different length after a
NBIO event could cause an OPENSSL_assert to be reached. The assert is not
actually necessary because there was an explicit check a little further
down that would catch this scenario. Therefore remove the assert an move
the check a little higher up.

Reviewed-by: Rich Salz <c04971a99e5a9ee80eaab4b1deb37e845b0bd697@openssl.org>

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl