GetObjectA: unlock the object again even in case of failure.

diff --git a/objects/gdiobj.c b/objects/gdiobj.c
index a94cd15..db559ea 100644
--- a/objects/gdiobj.c
+++ b/objects/gdiobj.c
@@ -650,7 +650,7 @@
 
       default:
           ERR("Invalid GDI Magic %04x\n", ptr->wMagic);
-	  return 0;
+          break;
     }
     GDI_ReleaseObj( handle );
     return result;