Wiki CI: require all devices to be booting

In gitlab, there is no extra CI job running for commits in a merge
request (MR). This means, we can't run different code in a MR against
"master".

So instead of only checking whether all devices are booting if there's
a MR against master, always perform this check.

I've edited the message slightly, so it's clear that it's only required
to have the devices booting when making a merge request against master.

.gitlab-ci.yml

@@ -22,7 +22,7 @@ stages:
 wiki-test:
   stage: checks
   script:
-    - "./test/check_devices_in_wiki.py"
+    - "./test/check_devices_in_wiki.py --booting"
 
 static-code-analysis:
   stage: checks

test/check_devices_in_wiki.py

@@ -68,8 +68,9 @@ def check_device(device, html, is_booting):
         return True
     if device in html["not_booting"]:
         if is_booting:
-            print(device + ": wrong section of the wiki, this should be in"
-                  " booting already")
+            print(device + ": still in 'not booting' section (if this is a"
+                  " merge request, your device should be in the booting"
+                  " section already)")
             return False
         return True