remote_logging_server: sleep at the end

It seems ending the test right after we create the mutex can
cause the client not to catch it, sometimes. So let's sleep for
a few seconds after creating it to make sure it does.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

needles/gnome/apps/maps/maps_route_bike_shown-20221224.json

@@ -0,0 +1,15 @@
+{
+  "area": [
+    {
+      "ypos": 354,
+      "height": 318,
+      "type": "match",
+      "xpos": 368,
+      "width": 102
+    }
+  ],
+  "properties": [],
+  "tags": [
+    "maps_route_bike_shown"
+  ]
+}

tests/server_remote_logging_client.pm

@@ -2,6 +2,7 @@ use base "installedtest";
 use strict;
 use testapi;
 use lockapi;
+use utils;
 
 sub run {
     my $self = shift;

tests/server_remote_logging_server.pm

@@ -3,6 +3,7 @@ use strict;
 use testapi;
 use lockapi;
 use mmapi;
+use utils;
 
 sub run {
     my $self = shift;
@@ -31,6 +32,8 @@ sub run {
     assert_script_run 'grep "XXX RSYSLOG TEST MESSAGE" /var/log/messages';
     # tell child test we were successful
     mutex_create("rsyslog_message_received");
+    # give it a few seconds to make sure the client gets it
+    sleep 10;
 }
 
 sub test_flags {