packaging: use rng-tools service name on SUSE 15 for management server

On SUSE 15 the rng-tools package ships the service as rng-tools.service,
not rngd.service, so enabling rngd silently failed.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: kiranchavala

packaging/suse15/cloud.spec

@@ -466,7 +466,7 @@ else
 fi
 
 /usr/bin/systemctl enable cloudstack-management > /dev/null 2>&1 || true
-/usr/bin/systemctl enable --now rngd > /dev/null 2>&1 || true
+/usr/bin/systemctl enable --now rng-tools > /dev/null 2>&1 || true
 
 grep -s -q "db.cloud.driver=jdbc:mysql" "%{_sysconfdir}/%{name}/management/db.properties" || sed -i -e "\$adb.cloud.driver=jdbc:mysql" "%{_sysconfdir}/%{name}/management/db.properties"
 grep -s -q "db.usage.driver=jdbc:mysql" "%{_sysconfdir}/%{name}/management/db.properties" || sed -i -e "\$adb.usage.driver=jdbc:mysql"  "%{_sysconfdir}/%{name}/management/db.properties"