units: disable start rate limit for systemd-vconsole-setup.service

The unit will be started or restarted a few times during boot, but but it has
StartLimitBurst = DefaultStartLimitBurst = 5, which means that the fifth
restart will already fail. On my laptop, I have exactly 4 restarts, so I don't
hit the limit, but on a slightly different system we will easily hit the limit.
In https://bugzilla.redhat.com/show_bug.cgi?id=2251394, there are five reloads
and we hit the limit.

Since 6ef512c we propagate the start counter
over switch-root and daemon reloads, so it's easier to hit the limit during
boot.

In principle there might be systems with lots of vtcon devices, so let's just
allow the unit to be restarted without a limit.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=2251394.

units/systemd-vconsole-setup.service.in

@@ -17,6 +17,12 @@ DefaultDependencies=no
 Before=sysinit.target
 Before=initrd-switch-root.target shutdown.target
 
+# This unit will be restarted by udev whenever a new vtcon device appears or is
+# triggered. Usually that happens just a handful of times during boot, but some
+# systems may have hundreds or thousands of serial consoles connected, so let's
+# just disable the limit altogether.
+StartLimitIntervalSec=0
+
 [Service]
 Type=oneshot
 # This service will be restarted by udev whenever a new vtcon device appears.