Revert "rsyslog: fix config file comment style"

This reverts commit d42f0f96, which
breaks the build since the patch being added by this commit is in fact
already part of the 8.9.0 rsyslog release we are using.

Indeed, in the rsyslog repository:

$ git tag --contains fe01c9ec4979c78b6a7caf045cab17ba52d4ad08
[...]
v8.10.0
v8.10.0.ad1
v8.11.0
v8.7.0
v8.8.0
v8.8.0.ad1
v8.9.0
v8.9.0.ad1

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>