Gio::Settings: Don't use the deprecated "schema" property
Gio::Settings: Don't use the deprecated "schema" property

* gio/src/settings.[hg|ccg]: Replace the deprecated "schema" property by
"schema_id" in constructors.

johne53/MB3Glibmm,johne53/MB3Glibmm,GNOME/glibmm,GNOME/glibmm,johne53/MB3Glibmm,GNOME/glibmm,johne53/MB3Glibmm,GNOME/glibmm,GNOME/glibmm