Fix configuration corruption issue

In the event that the configuration was corrupt the first time the
SSSD is started, it would write in the special data for attributes
and indexes, but it would fail before writing the version.

Subsequent reloads (even with correct configuration files) would
fail, since they would try again to write the attributes and
indexes and fail since they were already present.

server/monitor/monitor.c

@@ -1219,6 +1219,7 @@ int monitor_process_init(TALLOC_CTX *mem_ctx,
     struct sysdb_ctx *sysdb;
     struct tevent_signal *tes;
     int ret, i;
+    char *cdb_file;
     struct sss_domain_info *dom;
 
     ctx = talloc_zero(mem_ctx, struct mt_ctx);
@@ -1232,9 +1233,26 @@ int monitor_process_init(TALLOC_CTX *mem_ctx,
     /* Initialize the CDB from the configuration file */
     ret = confdb_test(ctx->cdb);
     if (ret == ENOENT) {
-        /* First-time setup
-         * Load special entries
+        /* First-time setup */
+
+        /* Purge any existing confdb in case an old
+         * misconfiguration gets in the way
          */
+        talloc_free(ctx->cdb);
+        cdb_file = talloc_asprintf(ctx, "%s/%s", DB_PATH, CONFDB_FILE);
+        if (cdb_file == NULL) {
+            DEBUG(0,("Out of memory, aborting!\n"));
+            return ENOMEM;
+        }
+
+        unlink(cdb_file);
+        ret = confdb_init(ctx, ctx->ev, &ctx->cdb, cdb_file);
+        if (ret != EOK) {
+            DEBUG(0,("The confdb initialization failed\n"));
+            return ret;
+        }
+
+        /* Load special entries */
         ret = confdb_create_base(cdb);
         if (ret != EOK) {
             talloc_free(ctx);