BUG/MINOR: config: make sure to count the error on incorrect track-sc/stick rules

When commit 151e1ca98 ("BUG/MAJOR: config: verify that targets of track-sc
and stick rules are present") added a check for some process inconsistencies
between rules and their stick tables, some errors resulted in a "return 0"
statement, which is taken as "no error" in some cases. Let's fix this.

This must be backported to all versions using the above commit.
diff --git a/src/sample.c b/src/sample.c
index 963cb59..16251f0 100644
--- a/src/sample.c
+++ b/src/sample.c
@@ -1267,7 +1267,8 @@
 			if (p->bind_proc & ~px->bind_proc) {
 				ha_alert("parsing [%s:%d] : stick-table '%s' not present on all processes covered by proxy '%s'.\n",
 					 cur->file, cur->line, px->id, p->id);
-				return 0;
+				cfgerr++;
+				break;
 			}
 
 			free(arg->data.str.area);