Change the Guest Agent log_dir to /var/log/trove

In trove-integration, a patch was submitted to change the value
of the log_dir variable in the trove-guestagent.conf.sample file.
This should be changed here as well so that devstack uses the same
location.

The devstack trove-guestagent.conf file is created by devstack, not
from the sample file, so it needs to be changed here.

(For reference, an actual trove-guestagent.conf file is created by
the cloud provider implementing Trove, who may or may not use the
sample file provided.)

See: https://review.openstack.org/#/c/157973

Change-Id: I41b8e6fe443a2eff376ffc1f92c2ed90c94530b0
diff --git a/lib/trove b/lib/trove
index d437718..080e860 100644
--- a/lib/trove
+++ b/lib/trove
@@ -180,7 +180,7 @@
     iniset $TROVE_CONF_DIR/trove-guestagent.conf DEFAULT trove_auth_url $TROVE_AUTH_ENDPOINT
     iniset $TROVE_CONF_DIR/trove-guestagent.conf DEFAULT control_exchange trove
     iniset $TROVE_CONF_DIR/trove-guestagent.conf DEFAULT ignore_users os_admin
-    iniset $TROVE_CONF_DIR/trove-guestagent.conf DEFAULT log_dir /tmp/
+    iniset $TROVE_CONF_DIR/trove-guestagent.conf DEFAULT log_dir /var/log/trove/
     iniset $TROVE_CONF_DIR/trove-guestagent.conf DEFAULT log_file trove-guestagent.log
     setup_trove_logging $TROVE_CONF_DIR/trove-guestagent.conf
 }