Revert "lava: Make the AUM tests logs work again the web UI"

This reverts commit 0dc36df3.

Revert this commit since it is breaking tests submission to LAVA with
`lqa` tool started in Apertis environment:

 Submitting job aum-ota-rollback-blacklist.yaml: <Fault 400: 'Problem
 with submitted job data: Loading job submission failed: while parsing
 a block mapping\n  in "<unicode string>", line 2, column 1\ndid not
 find expected key\n  in "<unicode string>", line 154, column 1.'>

Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>

lava/common-boot-tpl-reboot.yaml

-{% import 'common-boot-macros.yaml' as boot with context -%}
   - boot:
       namespace: system
       timeout: