Fix migration 016 for sqlite.

Sqlite doesn't support dropping a column from a table. The
downgrade path for migration 016 performed this. So this commit adds the
sql file to perform the downgrade manually.

Change-Id: I6aae263c3aab03a383c47fd29c46f0cc9b857549

glance/db/sqlalchemy/migrate_repo/versions/016_sqlite_downgrade.sql

@@ -0,0 +1,46 @@
+BEGIN TRANSACTION;
+
+CREATE TEMPORARY TABLE image_members_backup (
+    id INTEGER NOT NULL,
+    image_id VARCHAR(36) NOT NULL,
+    member VARCHAR(255) NOT NULL,
+    can_share BOOLEAN NOT NULL,
+    created_at DATETIME NOT NULL,
+    updated_at DATETIME,
+    deleted_at DATETIME,
+    deleted BOOLEAN NOT NULL,
+    PRIMARY KEY (id),
+    UNIQUE (image_id, member),
+    CHECK (can_share IN (0, 1)),
+    CHECK (deleted IN (0, 1)),
+    FOREIGN KEY(image_id) REFERENCES images (id)
+);
+
+INSERT INTO image_members_backup
+SELECT id, image_id, member, can_share, created_at, updated_at, deleted_at, deleted
+FROM image_members;
+
+DROP TABLE image_members;
+
+CREATE TABLE image_members (
+    id INTEGER NOT NULL,
+    image_id VARCHAR(36) NOT NULL,
+    member VARCHAR(255) NOT NULL,
+    can_share BOOLEAN NOT NULL,
+    created_at DATETIME NOT NULL,
+    updated_at DATETIME,
+    deleted_at DATETIME,
+    deleted BOOLEAN NOT NULL,
+    PRIMARY KEY (id),
+    UNIQUE (image_id, member),
+    CHECK (can_share IN (0, 1)),
+    CHECK (deleted IN (0, 1)),
+    FOREIGN KEY(image_id) REFERENCES images (id)
+);
+
+INSERT INTO image_members
+SELECT id, image_id, member, can_share, created_at, updated_at, deleted_at,     deleted
+FROM image_members_backup;
+
+DROP TABLE image_members_backup;
+COMMIT;