Increase guest os ready timeout

Rhel image is taking more than 60 seconds for starting
sometines and then we are seeing the paramiko issue with ssh
stablishment again(Bug: #1892861)
Original fix:
https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/758968

Change-Id: I06586175a1607775cc61d57703f26a9ad23123d9
diff --git a/neutron_tempest_plugin/scenario/base.py b/neutron_tempest_plugin/scenario/base.py
index 8591c89..6674cb8 100644
--- a/neutron_tempest_plugin/scenario/base.py
+++ b/neutron_tempest_plugin/scenario/base.py
@@ -534,7 +534,7 @@
             return False
 
         try:
-            utils.wait_until_true(system_booted, sleep=5)
+            utils.wait_until_true(system_booted, timeout=90, sleep=5)
         except utils.WaitTimeout:
             LOG.debug("No correct output in console of server %s found. "
                       "Guest operating system status can't be checked.",