ipaserver_prepare: Properly report error, do show trace back

The raises of RuntimeError, ValueError and ScriptError are currently not
properly handled in ipaserver_prepare. This results in a trace back error
shown in Ansible instead of only showing the error message.

This happened for example if a nameserver is in /etc/resolv.conf that is
not reachable.

roles/ipaserver/library/ipaserver_prepare.py

@@ -195,6 +195,8 @@ def main():
     if not options.ca_subject:
         options.ca_subject = str(default_ca_subject_dn(options.subject_base))
 
+    try:
+
         # Configuration for ipalib, we will bootstrap and finalize later, after
         # we are sure we have the configuration file ready.
         cfg = dict(
@@ -286,6 +288,10 @@ def main():
             if tasks.configure_pkcs11_modules(fstore):
                 ansible_log.info("Disabled p11-kit-proxy")
 
+    except (RuntimeError, ValueError, ScriptError,
+            ipautil.CalledProcessError) as e:
+        ansible_module.fail_json(msg=str(e))
+
     ansible_module.exit_json(changed=True,
                              ### basic ###
                              ip_addresses=[ str(ip) for ip in ip_addresses ],