Remove variable part of agent dict to fix AgentManagementTest

Agents may vary their configuration while API tests blindly
compare agent dicts. Need to pop items that may change.

Change-Id: I150f4e9f2e79f6e20f18dee69cf061c68a5bed68
Closes-Bug: #1299350
Merge "Remove variable part of agent dict to fix AgentManagementTest"