iostatus: change is_read to a bool

Do this while we are touching this part of the code, before introducing
more uses of "int is_read".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 1c3ebd7..0bae046 100644
--- a/block.c
+++ b/block.c
@@ -1387,7 +1387,7 @@
 }
 
 void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
-                               BlockErrorAction action, int is_read)
+                               BlockErrorAction action, bool is_read)
 {
     QObject *data;
     const char *action_str;
@@ -2481,7 +2481,7 @@
     bs->on_write_error = on_write_error;
 }
 
-BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, int is_read)
+BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, bool is_read)
 {
     return is_read ? bs->on_read_error : bs->on_write_error;
 }