Remove gvdb.wrap

It causes Meson to git clone gvdb when glib is a subproject instead of using the copy included in release tarball.

The wrap file does not contain any useful information any way, the git commit used is already defined in .gitmodules and it's better to not duplicate that information. The [provide] section only declare the "gvdb" dependency name which is implicit when the file is called "gvdb.wrap".