nodemap: deal with the "debugupdatecache" case using a "fake" transaction
We are going to need more and more methods of the transaction. So lets change
approach. The `hg debugupdatecache` case do not need a transaction, because has
the repositories locked, but is not adding any "store" data to it.
Differential Revision: https://phab.mercurial-scm.org/D8186
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install::
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing::
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.