[tracker] libtracker-data: Add missing unlock call

[Carlos Garnacho <carlosg src gnome org>]

commit 548c88c0f73efd9988584b5e716a8febee24de5d
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Nov 27 17:00:39 2016 +0100

    libtracker-data: Add missing unlock call
    
    If the sqlite3_stmt fails to be compiled, we would return without
    releasing the TrackerDBInterface mutex, not good.

 src/libtracker-data/tracker-db-interface-sqlite.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/src/libtracker-data/tracker-db-interface-sqlite.c 
b/src/libtracker-data/tracker-db-interface-sqlite.c
index 744cb2d..cb4f503 100644
--- a/src/libtracker-data/tracker-db-interface-sqlite.c
+++ b/src/libtracker-data/tracker-db-interface-sqlite.c
@@ -2183,8 +2183,10 @@ tracker_db_interface_create_statement (TrackerDBInterface           *db_interfac
                sqlite_stmt = tracker_db_interface_prepare_stmt (db_interface,
                                                                 full_query,
                                                                 error);
-               if (!sqlite_stmt)
+               if (!sqlite_stmt) {
+                       tracker_db_interface_unlock (db_interface);
                        return NULL;
+               }
 
                stmt = tracker_db_statement_sqlite_new (db_interface,
                                                        sqlite_stmt);