dbhub: Change schema of local database

Also delete the upgrade mechanism that was put in place because it won't
be that easy anyway later on.

src/RemoteDatabase.cpp

@@ -518,7 +518,7 @@ void RemoteDatabase::localAssureOpened()
                                 "\"name\" TEXT NOT NULL,"
                                 "\"url\" TEXT NOT NULL,"
                                 "\"commit_id\" TEXT NOT NULL,"
-                                "\"file\" INTEGER,"
+                                "\"file\" TEXT NOT NULL UNIQUE,"
                                 "\"modified\" INTEGER DEFAULT 0,"
                                 "\"branch\" TEXT NOT NULL DEFAULT \"master\""
                                 ")");
@@ -530,12 +530,6 @@ void RemoteDatabase::localAssureOpened()
         m_dbLocal = nullptr;
         return;
     }
-
-    // Add column "branch" if it doesn't exist yet. This isn't done in a particular nice way here because we just let the
-    // command fail if it already exists but whatever.
-    // NOTE that this code can be removed after releasing v3.11.0.
-    statement = QString("ALTER TABLE \"local\" ADD COLUMN \"branch\" TEXT NOT NULL DEFAULT \"master\"");
-    sqlite3_exec(m_dbLocal, statement.toUtf8(), NULL, NULL, NULL);
 }
 
 void RemoteDatabase::localAdd(QString filename, QString identity, const QUrl& url)