bookmark: do not crash when active bookmark is forward and --date is used
The logic that decides where to update according to the active bookmark
location (when not on ".") was setting the rev to update to before we process
--date. This lead to --date processing aborting because of duplicated
specification.
We reorder the two pieces of code and add a test for this.
Test issue2761
$ hg init
$ touch to-be-deleted
$ hg add
adding to-be-deleted
$ hg ci -m first
$ echo a > to-be-deleted
$ hg ci -m second
$ rm to-be-deleted
$ hg diff -r 0
Same issue, different code path
$ hg up -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ touch does-not-exist-in-1
$ hg add
adding does-not-exist-in-1
$ hg ci -m third
$ rm does-not-exist-in-1
$ hg diff -r 1