symbol.c (rb_sym2id): do not return garbage object

The dynamic sym passed to rb_sym2id may be a garbage object
(as accounted for by dsymbol_check).  This fixes an occasional
segfault in "make test-all" for me.

No need to backport, this is from the new symbol GC feature.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47322 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Sat Aug 30 19:22:47 2014  Eric Wong  <e@80x24.org>
+
+	* symbol.c (rb_sym2id): do not return garbage object
+
 Sat Aug 30 06:39:48 2014  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* ext/psych/lib/psych/visitors/yaml_tree.rb: fix NameError dumping and

symbol.c

@@ -759,7 +759,7 @@ rb_sym2id(VALUE sym)
     }
     else {
 	if (!SYMBOL_PINNED_P(sym)) {
-	    dsymbol_pindown(sym);
+	    return dsymbol_pindown(sym);
 	}
 	return (ID)sym;
     }