convert: added bookmarks support in filemap
When using the convert extension from a Mercurial rep. to subset it with
filemap, the bookmarks are not copied. I fixed this by calling the
base.get_bookmarks() from the filemap getbookmarks() instead of returning an
empty dictionary. It should work also for other converters that implement
getbookmarks() (like git). I don't see any drawbacks except that the bookmarks
are always copied (not necessarily wanted all the times).
util: fix finding of hgexecutable
The version introduced in
89d9f92f6fdd would for example return thg
(thanks to Mads Kiilerich for pointing to this)