Correct logic of module_exists, ensuring we correctly skip the debian.deb822...

Correct logic of module_exists, ensuring we correctly skip the debian.deb822 tests when python3-debian is not installed. (Closes: #854745)

Signed-off-by: Chris Lamb <lamby@debian.org>

tests/comparators/utils/tools.py

@@ -64,7 +64,7 @@ def get_supported_elf_formats():
 def skip_unless_module_exists(name):
     def module_exists(x):
         try:
-            return importlib.util.find_spec(x) is None
+            return importlib.util.find_spec(x) is not None
         except ImportError:
             # Probing for submodules (eg. ``debian.deb822``) will attempt to
             # import ``debian`` so we must handle that failing.