Stop mounting an emptyDir to /var/log

[JRBANCEL]

In what area(s)?

/area monitoring
/kind proposal

Describe the feature

This is a follow up to #818 and an attempt to fix #2142.

Here is a proposal: https://docs.google.com/document/d/1u-yL14tBtlBvnfAsd8I_eqzg-0gPvQwrCBJN4dSvB6U/edit?folder=10HcpZlI1PbFyzinO6HjfHbzCkBXrqXMy#

[knative-housekeeping-robot]

Issues go stale after 90 days of inactivity.
Mark the issue as fresh by adding the comment /remove-lifecycle stale.
Stale issues rot after an additional 30 days of inactivity and eventually close.
If this issue is safe to close now please do so by adding the comment /close.

Send feedback to Knative Productivity Slack channel or file an issue in knative/test-infra.

/lifecycle stale

[knative-housekeeping-robot]

Stale issues rot after 30 days of inactivity.
Mark the issue as fresh by adding the comment /remove-lifecycle rotten.
Rotten issues close after an additional 30 days of inactivity.
If this issue is safe to close now please do so by adding the comment /close.

Send feedback to Knative Productivity Slack channel or file an issue in knative/test-infra.

/lifecycle rotten

[knative-housekeeping-robot]

Rotten issues close after 30 days of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh by adding the comment /remove-lifecycle rotten.

Send feedback to Knative Productivity Slack channel or file an issue in knative/test-infra.

/close

[knative-prow-robot]

@knative-housekeeping-robot: Closing this issue.

In response to this:

Rotten issues close after 30 days of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh by adding the comment /remove-lifecycle rotten.

Send feedback to Knative Productivity Slack channel or file an issue in knative/test-infra.

/close

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