Add syslog option, off by default.

Add syslog option to glance and nova.
diff --git a/files/glance-registry.conf b/files/glance-registry.conf
index c3ca9a7..351b09f 100644
--- a/files/glance-registry.conf
+++ b/files/glance-registry.conf
@@ -19,7 +19,7 @@
 filesystem_store_datadir = %DEST%/glance/images
 
 # Send logs to syslog (/dev/log) instead of to file specified by `log_file`
-use_syslog = False
+use_syslog = %SYSLOG%
 
 # SQLAlchemy connection string for the reference implementation
 # registry server. Any valid SQLAlchemy connection string is fine.