bundle2: fix the formatting of the stream part requirements Use the same pre-encoded normalization as bundlespecs for the stream v2 part requirements. As it touch the wire protocol, it needs to change before the release. This was spotted by Gregory Szorc. Differential Revision: https://phab.mercurial-scm.org/D1950

streamclone: extract requirements formatting It will be reused for the formatting of the requirements of the stream v2 part requirement and later for the stream v2 requirements. Differential Revision: https://phab.mercurial-scm.org/D1949

bookmarks: fix pushkey compatibility mode (issue5777) The namespace used for the compatibility mode was missing a trailing 's'.