Add syslog option, off by default.

Add syslog option to glance and nova.
diff --git a/files/glance-api.conf b/files/glance-api.conf
index 0358a7a..3499ff7 100644
--- a/files/glance-api.conf
+++ b/files/glance-api.conf
@@ -27,7 +27,7 @@
 log_file = %DEST%/glance/api.log
 
 # Send logs to syslog (/dev/log) instead of to file specified by `log_file`
-use_syslog = False
+use_syslog = %SYSLOG%
 
 # ============ Notification System Options =====================