test/recipes/30-test_afalg.t: set OPENSSL_ENGINES correctly

The afalg engine was moved down from engines/afalg/ to engines/, but
the test wasn't changed accordingly.  This was undetected because the
test program didn't fail when it couldn't load the engine.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5270)

test/recipes/30-test_afalg.t

@@ -18,6 +18,6 @@ plan skip_all => "$test_name not supported for this build"
 
 plan tests => 1;
 
-$ENV{OPENSSL_ENGINES} = bldtop_dir("engines/afalg");
+$ENV{OPENSSL_ENGINES} = bldtop_dir("engines");
 
 ok(run(test(["afalgtest"])), "running afalgtest");