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/src/dumpstats.c b/src/dumpstats.c
index 142429b..16d07dd 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -2037,6 +2037,26 @@
 						     "Nothing has changed."
 						     "</div>\n", uri->uri_prefix);
 				}
+				else if (strcmp(si->applet.ctx.stats.st_code, STAT_STATUS_PART) == 0) {
+					chunk_printf(&msg,
+						     "<p><div class=active2>"
+						     "<a class=lfsb href=\"%s\" title=\"Remove this message\">[X]</a> "
+						     "Action partially processed.<br>"
+						     "Some server names are probably unknown or ambiguous (duplicated names in the backend)."
+						     "</div>\n", uri->uri_prefix);
+				}
+				else if (strcmp(si->applet.ctx.stats.st_code, STAT_STATUS_ERRP) == 0) {
+					chunk_printf(&msg,
+						     "<p><div class=active0>"
+						     "<a class=lfsb href=\"%s\" title=\"Remove this message\">[X]</a> "
+						     "Action not processed because of invalid parameters."
+						     "<ul>"
+						     "<li>The action is maybe unknown.</li>"
+						     "<li>The backend name is probably unknown or ambiguous (duplicated names).</li>"
+						     "<li>Some server names are probably unknown or ambiguous (duplicated names in the backend).</li>"
+						     "</ul>"
+						     "</div>\n", uri->uri_prefix);
+				}
 				else if (strcmp(si->applet.ctx.stats.st_code, STAT_STATUS_EXCD) == 0) {
 					chunk_printf(&msg,
 						     "<p><div class=active0>"