Fix a possible memleak in SRP_VBASE_new
In the error handling case the memory in
vb->users_pwd was accidentally not released.
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21981)