[ci] No longer pass '--privileged' option to slave container (sonic-net#1446)

Now that sonic-net/sonic-utilities#1427 has merged, we should be able to successfully run all unit tests in a non-privileged slave container.

Author: jleveque

azure-pipelines.yml

@@ -11,7 +11,6 @@ pool:
 
 container:
   image: sonicdev-microsoft.azurecr.io:443/sonic-slave-buster:latest
-  options: --privileged
 
 steps:
 - task: DownloadPipelineArtifact@2