ci/selftest: remove rm_work

oe-selftest is now logging having rm_work enabled as an error, which is
causing the test to fail.  Remove this from the selftest.yml file, and
everything works as before.

Signed-off-by: Jon Mason <jon.mason@arm.com>

ci/selftest.yml

@@ -7,3 +7,4 @@ local_conf_header:
   setup: |
     BB_LOGCONFIG = ""
     SANITY_TESTED_DISTROS = ""
+    INHERIT:remove = "rm_work"