ActiveSync: avoid "[ERROR] calendar: no database to synchronize"

The command line checks that a source has databases available.
That means that ActiveSyncSource::getDatabases() must at least
return one entry for the default database.

activesyncd commit ID:
6a95a911f2660fab7bea916e3607fa616b4e8b1e

src/backends/activesync/ActiveSyncSource.cpp

@@ -45,6 +45,15 @@ bool ActiveSyncSource::serverModeEnabled() const
     return m_operations.m_loadAdminData;
 }
 
+ActiveSyncSource::Databases ActiveSyncSource::getDatabases()
+{
+    Databases result;
+    // empty string always selects the default database
+    result.push_back(Database("", "", true));
+    return result;
+}
+
+
 void ActiveSyncSource::open()
 {
     // extract account ID and throw error if missing

src/backends/activesync/ActiveSyncSource.h

@@ -120,7 +120,7 @@ class ActiveSyncSource :
     /* partial implementation of SyncSource */
     virtual void enableServerMode();
     virtual bool serverModeEnabled() const;
-    virtual Databases getDatabases() { return Databases(); } // not supported
+    virtual Databases getDatabases();
     virtual void open();
     virtual void close();
     virtual std::string getPeerMimeType() const { return getMimeType(); }