update the branch cache at the end of addchangegroup
This should avoid a bad performance problem when the branch cache is
not up-to-date, and hgweb can't write an updated version because it
lacks permissions.
qpop/qrefresh: update self.applied before calling strip
This will be important for the next patch, which may end up using this
variable during an addchangegroup caused by strip.
hg import: write the dirstate after every commit
This allows the transaction system to backup the correct file, so
that a future rollback can do the right thing.
This should fix
issue963.