hacking: Modify checks for translated logs

The N319 check previously asserted that debug-level logs were not
translated. Now that we've removed all log translations, we can
generalize this to all logs. We reuse the same number since these
numbers are really just metadata and not public contracts.

This also allows us to update the N323 and N326 checks, which ensure we
import the translation function, '_', wherever it's used and don't
concatenate translated and non-translated strings. Since we're no longer
translating logs and the '_LE', '_LW' and '_LI' symbols are no longer
provided, we don't need to consider logs in either of these cases.

Change-Id: I64d139ad660bc382e8b9d7c8cd03352b26aadafd
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

HACKING.rst

@@ -25,7 +25,7 @@ Nova Specific Commandments
   assertIsInstance(A, B).
 - [N317] Change assertEqual(type(A), B) by optimal assert like
   assertIsInstance(A, B)
-- [N319] Validate that debug level logs are not translated.
+- [N319] Validate that logs are not translated.
 - [N320] Setting CONF.* attributes directly in tests is forbidden. Use
   self.flags(option=value) instead.
 - [N322] Method's default argument shouldn't be mutable