fix bond_8023ad_with_lacp_rate_fast

looks like we have an issue in test https://desktopqe-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/job/beaker-NetworkManager-main-veth-rhel8-upstream/914/artifact/artifacts/FAIL_report_NetworkManager-ci_Test0050_bond_8023ad_with_lacp_rate_fast.html

Then " 802.3ad info\s+LACP rate: fast " is visible with command " cat /proc/net/bonding/nm-bond " (2.016s) 
vs 
802.3ad info
LACP active: on
LACP rate: fast
Min links: 0
Aggregator selection policy (ad_select): stable
System priority: 65535
System MAC address: 16:21:4d:db:e5:df
Active Aggregator Info:
	Aggregator ID: 1
	Number of ports: 1
	Actor Key: 15
	Partner Key: 1
	Partner Mac Address: 00:00:00:00:00:00