Remove access to vertex container in MuZTPMon (ATR-19997)

Remove access to vertex container in MuZTPMon, which is not really used, but causes crashes in athenaMT output (due to access of null container)

added bugfix urgent labels

This merge request affects 1 package:

• Trigger/TrigMonitoring/TrigMuonMonitoring

added Trigger master review-pending-level-1 labels

Tagging @ynoguchi for info.

Hi. I'm the current MR L1 shifter and I'll be signing out for the day. The change looks ok, so if the CI job is successful I'm ok with approving. I'll try to check on it later tonight.

CI Result SUCCESS

	Athena	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available at NICOS MR-24841-2019-07-12-18-49
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 1108]

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 7afc8fcc

added sweep:ignore label