lib/ironic: Do not check for database or message queue

Only check for OpenStack services, not specific database or
messaging backends.

Change-Id: I7960718defa3f521d1c2128d8523e8ee9328da64
diff --git a/lib/ironic b/lib/ironic
index b99e325..a7738bc 100644
--- a/lib/ironic
+++ b/lib/ironic
@@ -181,7 +181,7 @@
 # install_ironic() - Collect source and prepare
 function install_ironic {
     # make sure all needed service were enabled
-    local req_services="mysql rabbit key"
+    local req_services="key"
     if [[ "$VIRT_DRIVER" == "ironic" ]]; then
         req_services+=" nova glance neutron"
     fi