i18n - Make string translatable

Since internationalization should be enabled in Watcher, this
patchset refactors the Watcher codebase to wrap previously
untranslatable strings with i18n translation functions so we can
import them for translation into the .pot template file.

Partially Implements: blueprint support-translation
Change-Id: I425967a60b5a7957f753894e5d2ba0d2c5009d1d

watcher/applier/manager.py

@@ -89,5 +89,5 @@ class ApplierManager(MessagingCore):
             LOG.debug("type_event => %s" % str(event_type))
             LOG.debug("data       => %s" % str(data))
         except Exception as e:
-            LOG.error("evt %s" % e.message)
-            raise e
+            LOG.exception(e)
+            raise

watcher/applier/primitives/change_nova_service_state.py

@@ -20,7 +20,7 @@
 
 from oslo_config import cfg
 
-
+from watcher._i18n import _
 from watcher.applier.primitives.base import BasePrimitive
 from watcher.applier.primitives.wrapper.nova_wrapper import NovaWrapper
 from watcher.applier.promise import Promise
@@ -70,7 +70,8 @@ class ChangeNovaServiceState(BasePrimitive):
 
     def nova_manage_service(self, state):
         if state is None:
-            raise IllegalArgumentException("The target state is not defined")
+            raise IllegalArgumentException(
+                _("The target state is not defined"))
 
         keystone = KeystoneClient()
         wrapper = NovaWrapper(keystone.get_credentials(),

watcher/applier/rpcapi.py

@@ -20,7 +20,6 @@ from oslo_config import cfg
 from oslo_log import log
 import oslo_messaging as om
 
-
 from watcher.applier.manager import APPLIER_MANAGER_OPTS
 from watcher.applier.manager import opt_group
 from watcher.common import exception
@@ -69,5 +68,5 @@ class ApplierAPI(MessagingCore):
         try:
             pass
         except Exception as e:
-            LOG.error("evt %s" % e.message)
-            raise e
+            LOG.exception(e)
+            raise