Remove useless SQL file

MANIFEST.in

@@ -1 +1 @@
-include COPYING NEWS.rst TODO.rst README.rst config logging radicale.py radicale.fcgi radicale.wsgi schema.sql
+include COPYING NEWS.rst TODO.rst README.rst config logging radicale.py radicale.fcgi radicale.wsgi

schema.sql

@@ -1,31 +0,0 @@
--- This is the database schema for PostgreSQL and MySQL and SQLite.
-
-create table collection (
-       path varchar(200) not null,
-       parent_path varchar(200) references collection (path),
-       primary key (path));
-
-create table item (
-       name varchar(200) not null,
-       tag text not null,
-       collection_path varchar(200) references collection (path),
-       primary key (name));
-
-create table header (
-       name varchar(200) not null,
-       value text not null,
-       collection_path varchar(200) references collection (path),
-       primary key (name, collection_path));
-
-create table line (
-       name text not null,
-       value text not null,
-       item_name varchar(200) references item (name),
-       timestamp bigint not null,
-       primary key (timestamp));
-
-create table property (
-       name varchar(200) not null,
-       value text not null,
-       collection_path varchar(200) references collection (path),
-       primary key (name, collection_path));