ipa systemd unit should define Wants=network instead of Requires=network

The file ipa.service defines
    Requires=network.target
which means that ipa stack will be restarted each time the network stack
is restarted. This is not needed, and Wants=network.target will be sufficient.

https://fedorahosted.org/freeipa/ticket/6723

Reviewed-By: Tomas Krizek <tkrizek@redhat.com>

init/systemd/ipa.service.in

@@ -1,6 +1,6 @@
 [Unit]
 Description=Identity, Policy, Audit
-Requires=network.target
+Wants=network.target
 Wants=gssproxy.service
 After=network.target