test: skip TEST-69-SHUTDOWN on Debian

There is a regression in the login package, skip the test until
it is fixed. https://bugs.debian.org/1075733

(cherry picked from commit 92d9d5ca70b0a8b3aea12f24e9cd0f770c31a94c)

test/units/TEST-69-SHUTDOWN.py

@@ -9,6 +9,13 @@ import pexpect
 
 
 def main():
+    # TODO: drop once https://bugs.debian.org/1075733 is fixed
+    with open("/usr/lib/os-release") as f:
+        for line in f:
+            if line.startswith("ID="):
+                if "debian" in line:
+                    sys.exit(77)
+
     logger = logging.getLogger("test-shutdown")
 
     consoles = []