MINOR: stats: add ST_SHOWADMIN to pass the admin info in the regular flags

It's easier to have a new flag in <flags> to indicate whether or not we
want to display the admin column in HTML dumps. We already have similar
flags to show the version or the legends.
diff --git a/include/common/uri_auth.h b/include/common/uri_auth.h
index 495d240..e80722d 100644
--- a/include/common/uri_auth.h
+++ b/include/common/uri_auth.h
@@ -31,6 +31,7 @@
 #define	ST_SHDESC	0x00000004	/* show description */
 #define	ST_SHLGNDS	0x00000008	/* show legends */
 #define	ST_CONVDONE	0x00000010	/* req_acl conversion done */
+#define	ST_SHOWADMIN	0x00000020	/* show the admin column */
 
 /* later we may link them to support multiple URI matching */
 struct uri_auth {