settings: Put logs directory in user directory

Instead of writing to a location we can't write to
when running as a regular user, refer to a user
specific path, and use os.path.expanduser to handle
the references to ~.
Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

avocado/core/data_dir.py

@@ -32,7 +32,7 @@ def get_logs_dir():
     if settings.intree:
         return os.path.join(get_root_dir(), 'logs')
     else:
-        return settings.get_value('runner', 'logs_dir')
+        return os.path.expanduser(settings.get_value('runner', 'logs_dir'))
 
 
 def get_tmp_dir():

etc/settings.ini

 [runner]
 root_dir = /usr/share/avocado
 test_dir = /usr/share/avocado/tests
-logs_dir = /var/log/avocado
+logs_dir = ~/avocado/logs
 tmp_dir = /tmp