qapi: Tighten qmp_input_end_list()

The only way that qmp_input_pop() will set errp is if a dictionary
was the most recent thing pushed.  Since we don't have any
push(struct)/pop(list) or push(list)/pop(struct) mismatches (such
a mismatch is a programming bug), we therefore cannot set errp
inside qmp_input_end_list().  Make this obvious by
using &error_abort.  A later patch will then remove the errp
parameter of qmp_input_pop(), but that will first require the
larger task of splitting visit_end_struct().
Signed-off-by: NEric Blake <eblake@redhat.com>
Message-Id: <1454075341-13658-23-git-send-email-eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

qapi/qmp-input-visitor.c

@@ -206,7 +206,7 @@ static void qmp_input_end_list(Visitor *v, Error **errp)
 {
     QmpInputVisitor *qiv = to_qiv(v);
 
-    qmp_input_pop(qiv, errp);
+    qmp_input_pop(qiv, &error_abort);
 }
 
 static void qmp_input_get_next_type(Visitor *v, const char *name, QType *type,