don't automatically unmap buffers when they're freed

this is in preparation to an api change wrt gralloc map/unmap
diff --git a/modules/gralloc/gralloc.cpp b/modules/gralloc/gralloc.cpp
index 67febd8..abb8c96 100644
--- a/modules/gralloc/gralloc.cpp
+++ b/modules/gralloc/gralloc.cpp
@@ -260,8 +260,8 @@
     }
     
     if (hnd->base) {
-        LOGW("Freeing mapped handle %p", hnd);
-        gralloc_unmap((gralloc_module_t*) dev->common.module, handle);
+        LOGW("handle %p still mapped at %p", hnd, hnd->base);
+        //gralloc_unmap((gralloc_module_t*) dev->common.module, handle);
     }
     
     close(hnd->fd);