Set a sane default for state_path

This change sets a sane default to state_path and puts the previous
state_path for tests only.

Because the default value of state_path changed, if this one isn't set in the
configuration file, pybasedir is not more used as replacement but /var/lib/nova
is used instead.

UpgradeImpact
DocImpact
Closes bug: #1240879

Change-Id: I94502bcfac8b372271acd0dbc1710c0e3009b8e1

etc/nova/nova.conf.sample

@@ -97,7 +97,7 @@
 
 # Top-level directory for maintaining nova's state (string
 # value)
-#state_path=$pybasedir
+#state_path=/var/lib/nova
 
 
 #

nova/paths.py

@@ -31,7 +31,7 @@ path_opts = [
                default=os.path.join(sys.prefix, 'local', 'bin'),
                help='Directory where nova binaries are installed'),
     cfg.StrOpt('state_path',
-               default='$pybasedir',
+               default='/var/lib/nova',
                help="Top-level directory for maintaining nova's state"),
 ]
 

nova/tests/conf_fixture.py

@@ -16,6 +16,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import os
+
 from oslo.config import cfg
 
 
@@ -43,6 +45,8 @@ class ConfFixture(config_fixture.Config):
     """Fixture to manage global conf settings."""
     def setUp(self):
         super(ConfFixture, self).setUp()
+        self.conf.set_default('state_path', os.path.abspath(
+            os.path.join(os.path.dirname(__file__), '..', '..')))
         self.conf.set_default('api_paste_config',
                               paths.state_path_def('etc/nova/api-paste.ini'))
         self.conf.set_default('host', 'fake-mini')