Initialize reseed_gen_counter to 1, like it is done in master

Reviewed-by: NMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
Reviewed-by: NPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/7532)

crypto/rand/drbg_lib.c

@@ -359,7 +359,7 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg,
     }
 
     drbg->state = DRBG_READY;
-    drbg->reseed_gen_counter = 0;
+    drbg->reseed_gen_counter = 1;
     drbg->reseed_time = time(NULL);
     tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
 
@@ -451,7 +451,7 @@ int RAND_DRBG_reseed(RAND_DRBG *drbg,
         goto end;
 
     drbg->state = DRBG_READY;
-    drbg->reseed_gen_counter = 0;
+    drbg->reseed_gen_counter = 1;
     drbg->reseed_time = time(NULL);
     tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);