cephadm: pin pyfakefs version for tox tests

5.4.0 seems to have caused a number of permission issues
in the test. In order to unblock make check, let's pin it
to 5.3.5 for now.

Signed-off-by: Adam King <[email protected]>

Author: adk3798

src/cephadm/tox.ini

@@ -28,7 +28,7 @@ skip_install=true
 deps =
   -rzipapp-reqs.txt
   pyfakefs == 4.5.6 ; python_version < "3.7"
-  pyfakefs >= 5, < 6 ; python_version >= "3.7"
+  pyfakefs == 5.3.5 ; python_version >= "3.7"
   mock
   pytest
   pyyaml