lib: add api method to read current config path

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
diff --git a/lib/command.c b/lib/command.c
index 56220da..12e8bb1 100644
--- a/lib/command.c
+++ b/lib/command.c
@@ -4108,6 +4108,12 @@
   host.config = XSTRDUP (MTYPE_HOST, filename);
 }
 
+const char *
+host_config_get (void)
+{
+  return host.config;
+}
+
 void
 install_default (enum node_type node)
 {