fix: Handle non-existence of /var/cache/cloud-what gracefully

* Card ID: CCT-2021
* When the directory `/var/cache/cloud-what` does not exists,
  then handle this situation gracefully
* TODO: Unit tests of rhsm-debug expects existence of some
  directories in the system. The whole root directory should
  be mocked and rhsm-debug should use this mock in unit tests.

Signed-off-by: Jiri Hnidek <jhnidek@redhat.com>

Author: jirihnidek

src/rhsm_debug/debug_commands.py

@@ -166,7 +166,8 @@ def _do_command(self):
                 self._copy_directory("/var/lib/rhsm", content_path)
 
             # sosreport does not collect /var/cache/cloud-what/*. It is our duty to collect it
-            self._copy_directory("/var/cache/cloud-what", content_path)
+            if os.path.isdir("/var/cache/cloud-what"):
+                self._copy_directory("/var/cache/cloud-what", content_path)
 
             if not sos:
                 self._copy_cert_directory(DEFAULT_PRODUCT_CERT_DIR, content_path)