[shotwell] Fix start-up error when faces is disabled

[Jens Georg <jensgeorg src gnome org>]

commit a8c366c26d9163694856462ee432c17fc73b2c87
Author: Jens Georg <mail jensge org>
Date:   Wed Feb 20 21:39:53 2019 +0100

    Fix start-up error when faces is disabled
    
    If there is no faces, then there will no database upgrade.

 src/db/DatabaseTable.vala | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/src/db/DatabaseTable.vala b/src/db/DatabaseTable.vala
index 293d7546..64ef9cd7 100644
--- a/src/db/DatabaseTable.vala
+++ b/src/db/DatabaseTable.vala
@@ -21,7 +21,11 @@ public abstract class DatabaseTable {
      * tables are created on demand and tables and columns are easily ignored when already present.
      * However, the change should be noted in upgrade_database() as a comment.
      ***/
+#if ENABLE_FACES
     public const int SCHEMA_VERSION = 21;
+#else
+    public const int SCHEMA_VERSION = 20;
+#endif
     
     protected static Sqlite.Database db;