revset: include the correct first ancestor change for follow(file)
Previously we always included '.', which may not touch a file.
Instead, find the file revision present in '.' and add its linkrev.
This matches the results of 'hg log --follow file'.
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
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.