Fix ordering issue in varpol::remove_node

[Jan Hubicka]

Hi,
this patch fixes ordering issue in varpool.c that, while removing alias
it first removes link to its target and then tries to copy the constructor.

Bootstrapped/regtested x86_64-linux, commited.
        PR ipa/61548
        * varpool.c (varpool_node::remove): Fix order of variables.
Index: varpool.c
===================================================================
--- varpool.c   (revision 220417)
+++ varpool.c   (working copy)
@@ -195,7 +195,6 @@ void
 varpool_node::remove (void)
 {
   symtab->call_varpool_removal_hooks (this);
-  unregister ();
 
   /* When streaming we can have multiple nodes associated with decl.  */
   if (symtab->state == LTO_STREAMING)
@@ -205,6 +204,8 @@ varpool_node::remove (void)
   else if (DECL_INITIAL (decl) && DECL_INITIAL (decl) != error_mark_node
           && !ctor_useable_for_folding_p ())
     remove_initializer ();
+
+  unregister ();
   ggc_free (this);
 }