mercurial: use tags module as repo function is deprecated as of 4.2

vcsserver/hg.py

@@ -33,8 +33,8 b' from vcsserver.hgcompat import ('
     archival, bin, clone, config as hgconfig, diffopts, hex,
     hg_url as url_parser, httpbasicauthhandler, httpdigestauthhandler,
     httppeer, localrepository, match, memctx, exchange, memfilectx, nullrev,
-    patch, peer, revrange, ui, Abort, LookupError, RepoError, RepoLookupError,
-    InterventionRequired, RequirementError)
+    patch, peer, revrange, ui, hg_tag, Abort, LookupError, RepoError,
+    RepoLookupError, InterventionRequired, RequirementError)
 
 log = logging.getLogger(__name__)
 
@@ -629,7 +629,7 b' class HgRemote(object):'
 
         date = (tag_time, tag_timezone)
         try:
-            repo.tag(name, node, message, local, user, date)
+            hg_tag.tag(repo, name, node, message, local, user, date)
         except Abort as e:
             log.exception("Tag operation aborted")
             # Exception can contain unicode which we convert

vcsserver/hgcompat.py

@@ -36,6 +36,7 b' from mercurial import unionrepo'
 from mercurial import localrepo
 from mercurial import merge as hg_merge
 from mercurial import subrepo
+from mercurial import tags as hg_tag
 
 from mercurial.commands import clone, nullid, pull
 from mercurial.context import memctx, memfilectx