waterfalls/cvo-waterfall: Soften the log regexp's ^ anchor

Must-gather includes a timestamp prefix:

  $ curl -s --compressed https://storage.googleapis.com/origin-ci-test/pr-logs/pull/openshift_cluster-version-operator/178/pull-ci-openshift-cluster-version-operator-master-e2e-aws-upgrade/134/artifacts/e2e-aws-upgrade/must-gather/namespaces/openshift-cluster-version/pods/cluster-version-operator-7cb5846b6b-ljbd5/cluster-version-operator/cluster-version-operator/logs/current.log | grep 'Running sync' | tail -n1
  2019-06-13T15:50:32.447432391Z I0613 15:50:32.447421       1 sync_worker.go:574] Running sync for clusteroperator "kube-apiserver" (48 of 381)

Author: wking

waterfall/cvo-waterfall.py

@@ -8,7 +8,7 @@
 import sys
 
 
-log_regexp = re.compile('^I[0-9]+ ([0-9:.]+) .* (Running sync|Done syncing) for ([^ ]+) "([^"]+)" \(([0-9]+) of ([0-9]+)\)')
+log_regexp = re.compile('^.*I[0-9]+ ([0-9:.]+) .* (Running sync|Done syncing) for ([^ ]+) "([^"]+)" \(([0-9]+) of ([0-9]+)\)')
 
 resources = {}
 reference_time = last_log = None