* in _InitRng(), remove "drbg_instantiated" conditional cleanup logic (Coverity true-benign-positive: DEADCODE because drbg_instantiated is always false when ret != DRBG_SUCCESS);
* fix clang-diagnostic-unreachable-code in wc_GenerateSeed();
* in wc_GenerateSeed(), move the gate closures for !FORCE_FAILURE_RDSEED and !ENTROPY_MEMUSE_FORCE_FAILURE to follow the /dev/urandom fallback method.