identify: build the tag list directly instead of using wctx.tags()
The current implementation of workingctx.tags() returns the tags of the parents.
This causes the calculation of {lastesttagdistance} from wdir() to be wrong.
The value when updated to a tag is 0, but updated to the tag's child is 2, the
child of that 3, and so on. This prepares for workingctx.tags() to not report
the parent tags.
Issue1678: IndexError when pushing
setting up base repo
$ hg init a
$ cd a
$ touch a
$ hg ci -Am a
adding a
$ cd ..
cloning base repo
$ hg clone a b
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd b
setting up cset to push
$ hg up null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ touch a
different msg so we get a clog new entry
$ hg ci -Am b
adding a
created new head
pushing
$ hg push -f ../a
pushing to ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
$ cd ..