PR: 1794

Submitted by: Peter Sylvester <peter.sylvester@edelweb.fr>
Reviewed by: steve

Remove unnecessary code for srp and to add some comments to
s_client.

- the callback to provide a user during client connect is
no longer necessary since rfc 5054 a connection attempt
with an srp cipher and no user is terminated when the
cipher is acceptable

- comments to indicate in s_client the (non-)usefulness of
th primalaty tests for non known group parameters.

ssl/s3_lib.c

@@ -3674,10 +3674,6 @@ long ssl3_ctx_callback_ctrl(SSL_CTX *ctx, int cmd, void (*fp)(void))
 		ctx->srp_ctx.srp_Mask|=SSL_kSRP;
 		ctx->srp_ctx.SRP_give_srp_client_pwd_callback=(char *(*)(SSL *,void *))fp;
 		break;
-	case SSL_CTRL_SET_TLS_EXT_SRP_MISSING_CLIENT_USERNAME_CB:
-		ctx->srp_ctx.srp_Mask|=SSL_kSRP;
-		ctx->srp_ctx.SRP_TLS_ext_missing_srp_client_username_callback=(char *(*)(SSL *,void *))fp;
-		break;
 #endif
 #endif
 	default: