MINOR: stats admin: allow unordered parameters in POST requests

Previously, the stats admin page required POST parameters to be provided
exactly in the same order as the HTML form.
This patch allows to handle those parameters in any orders.

Also, note that haproxy won't alter server states anymore if backend or server
names are ambiguous (duplicated names in the configuration) to prevent
unexpected results (the same should probably be applied to the stats socket).
diff --git a/include/proto/dumpstats.h b/include/proto/dumpstats.h
index eb44a36..4c3837b 100644
--- a/include/proto/dumpstats.h
+++ b/include/proto/dumpstats.h
@@ -58,8 +58,10 @@
 /* status codes (strictly 4 chars) used in the URL to display a message */
 #define STAT_STATUS_UNKN "UNKN"	/* an unknown error occured, shouldn't happen */
 #define STAT_STATUS_DONE "DONE"	/* the action is successful */
+#define STAT_STATUS_PART "PART"	/* the action is partially successful */
 #define STAT_STATUS_NONE "NONE"	/* nothing happened (no action chosen or servers state didn't change) */
-#define STAT_STATUS_EXCD "EXCD"	/* an error occured becayse the buffer couldn't store all data */
+#define STAT_STATUS_ERRP "ERRP"	/* an error occured due to invalid values in parameters */
+#define STAT_STATUS_EXCD "EXCD"	/* an error occured because the buffer couldn't store all data */
 #define STAT_STATUS_DENY "DENY"	/* action denied */
 
 extern struct si_applet http_stats_applet;