Handle SSSD restart crash more gently.

In ipa-client-install, failure of restart of sssd service no longer
causes the crash of the install process. Adds a warning message to
the root logger instead.

https://fedorahosted.org/freeipa/ticket/2827

ipa-client/ipa-install/ipa-client-install

@@ -437,7 +437,10 @@ def uninstall(options, env):
             "Original configuration file was restored, restarting SSSD " +
             "service.")
         sssd = ipaservices.service('sssd')
-        sssd.restart()
+        try:
+            sssd.restart()
+        except CalledProcessError:
+            root_logger.warning("SSSD service restart was unsuccessful.")
 
     if not options.unattended:
         root_logger.info(