Load server plugins in certmonger renewal helper

The certmonger renewal helper needs to load server plugins to
operate.  Initialise the API with in_server=True.

Fixes: https://fedorahosted.org/freeipa/ticket/5943
Reviewed-By: Jan Cholasta <jcholast@redhat.com>

install/certmonger/dogtag-ipa-ca-renew-agent-submit

@@ -445,7 +445,7 @@ def main():
         'ipaCACertRenewal':     renew_ca_cert,
     }
 
-    api.bootstrap(context='renew')
+    api.bootstrap(in_server=True, context='renew')
     api.finalize()
 
     operation = os.environ.get('CERTMONGER_OPERATION')