Job: give warning on both the UI and LOG

The recently introduced feature on job category would produce warnings
that wouldn't be visible in the logs because the log initialization is
done later (requires a log directory to be defined).

Let's create the category after the log has been sucessfully
initialized, and while at it, also show the warning in the UI.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

avocado/core/job.py

@@ -167,6 +167,7 @@ class Job:
         self._setup_job_results()
         self.result = result.Result(self)
         self.__start_job_logging()
+        self._setup_job_category()
         # Use "logdir" in case "keep_tmp" is enabled
         if getattr(self.args, "keep_tmp", None) == "on":
             base_tmpdir = self.logdir
@@ -204,8 +205,6 @@ class Job:
             id_file_obj.flush()
             os.fsync(id_file_obj)
 
-        self._setup_job_category()
-
     def _setup_job_category(self):
         """
         This has to be called after self.logdir has been defined
@@ -222,8 +221,10 @@ class Job:
             return
 
         if category != astring.string_to_safe_path(category):
-            LOG_JOB.warning("Unable to set category in job results: name is not "
-                            "filesystem safe: %s", category)
+            msg = ("Unable to set category in job results: name is not "
+                   "filesystem safe: %s" % category)
+            LOG_UI.warning(msg)
+            LOG_JOB.warning(msg)
             return
 
         # we could also get "base_logdir" from args, but I believe this is
@@ -240,7 +241,9 @@ class Job:
             os.symlink(os.path.relpath(self.logdir, category_path),
                        os.path.join(category_path, os.path.basename(self.logdir)))
         except Exception:
-            LOG_JOB.warning("Unable link this job to category %s", category)
+            msg = "Unable to link this job to category %s" % category
+            LOG_UI.warning(msg)
+            LOG_JOB.warning(msg)
 
     def __start_job_logging(self):
         # Enable test logger