Stop trying to create the 'ironic' user twice

After 09bd7c8fd5a6 landed, a conflict between lib/ironic and
extras.d/50-ironic.sh was exposed, breaking Ironic's check and gate
tests.

This resolves that conflict by only creating the 'ironic' user once.

Change-Id: Ic41517f0977c84a82f92f58565aaee6b5cc7eb3e
diff --git a/lib/ironic b/lib/ironic
index 607b131..f445474 100644
--- a/lib/ironic
+++ b/lib/ironic
@@ -186,9 +186,6 @@
     $IRONIC_BIN_DIR/ironic-dbsync
 
     create_ironic_cache_dir
-
-    # Create keystone artifacts for Ironic.
-    create_ironic_accounts
 }
 
 # start_ironic() - Start running processes, including screen