console_login: sleep a bit before starting

Summary:
This is a bit icky, but it's the easiest way to solve a problem
I've seen a few times, the latest case being
https://openqa.stg.fedoraproject.org/tests/1664 . In that test,
_console_wait_login logs in to tty1 as user, then uefi_
postinstall wants to switch to tty3 and log in as root. When
it does that, sometimes the check_screen loop in console_login
gets hit before the display has actually switched from tty1 to
tty3, so everything gets out of sync.

An alternative would be to have root_console check that it's
either logged in or at the correct tty before handing off to
console_login, but that starts duplicating stuff, and it breaks
in the case the target tty is logged in as a user and the login
prompt is no longer visible...

Test Plan:
Check all tests run as normal, and maybe run UEFI
tests a few times to see that the bug no longer happens (but
it's hard to reliably trigger it anyway).

Reviewers: garretraziel, jskladan

Reviewed By: jskladan

Subscribers: tflink

Differential Revision: https://phab.qadevel.cloud.fedoraproject.org/D683

lib/fedorabase.pm

@@ -17,6 +17,14 @@ sub console_login {
         check => 1,
         @_);
 
+    # There's a timing problem when we switch from a logged-in console
+    # to a non-logged in console and immediately call this function;
+    # if the switch lags a bit, this function will match one of the
+    # logged-in needles for the console we switched from, and get out
+    # of sync (e.g. https://openqa.stg.fedoraproject.org/tests/1664 )
+    # To avoid this, we'll sleep a couple of seconds before starting
+    sleep 2;
+
     my $good = "";
     my $bad = "";
     my $needuser = 1;