narrow: send specs as bundle2 data instead of param (issue5952) (issue6019) Before this patch, when ACL is involved, narrowspecs are send as bundle2 parameter for narrow:spec bundle2 part. The limitation of bundle2 parts are they cannot send data larger than 255 bytes. Includes and excludes in narrow are not limited by size and they can grow over 255 bytes. This patch start sending them as bundle2 data. After this change, we try to read specs both from parameters and data, making it compatible with older servers. Differential Revision: https://phab.mercurial-scm.org/D6218