dhcp: cleanup formatting of LOG_LEASE() macro in lease_to_ip4_config()

and lease_to_ip6_config().

The use of a prefix should be done by LOG_LEASE() macro, instead
of each caller individually.

src/dhcp/nm-dhcp-systemd.c

@@ -212,7 +212,7 @@ add_requests_to_options (GHashTable *options, const ReqOption *requests)
 #define LOG_LEASE(domain, ...) \
 G_STMT_START { \
 	if (log_lease) { \
-		_LOG2I ((domain), (iface), __VA_ARGS__); \
+		_LOG2I ((domain), (iface), "  "__VA_ARGS__); \
 	} \
 } G_STMT_END