Migrated org.gnome.evolution.shell.network-config.gschema.xml.in to data/ directory.

The gsettings schemas need to all be stored and installed from the data/
directory, this is because we compile them locally in-tree and set the
GSETTINGS_SCHEMA_DIR to a local directory in order to run our tests
at make check time (tests dont work without this, instead GSettings wants
to abort for a missing schema).