Set RANDFILE=/dev/null for ipa-server-configure-first.service

OpenSSL requires at least one of HOME or RANDFILE environment
variables to be set for it to work.

Without this fix, the external CA setup crashes because OpenSSL
is unable to write its random state anywhere when it tries to
generate a CSR for the external CA to sign.

ipa-server-configure-first.service

@@ -3,6 +3,7 @@ Description=Configure IPA server upon the first start
 
 [Service]
 Type=oneshot
+Environment="RANDFILE=/dev/null"
 ExecStart=/usr/sbin/ipa-server-configure-first
 ExecStartPost=/usr/sbin/ipa-server-status-check
 FailureAction=poweroff