commands: add value for cmdtype argument for read only commands
In the previous release we added an argument `cmdtype` to registrar.command()
which is a enum and tells whether the command is read only, recoverable write or
unrecoverable write command. This patch add the value of cmdtype argument for
commands which are read only.
Differential Revision: https://phab.mercurial-scm.org/D1468
test-convert-git.t
test-subrepo-git.t
test-patchbomb-tls.t