killdaemons: drop superfluous L suffix from constant

As far as I'm aware PEP 237[0] means this suffix is superfluous even
on Python 2.4, and we can just drop it, which makes this code happy on
Python 3.

0: http://legacy.python.org/dev/peps/pep-0237/
fix_bytesmod: use the "from mercurial" form of the import to avoid breaking httpclient

Without this patch, 2to3's rewrites to httpclient cause it to fail to
import. With this patch, it's probably hopelessly broken, but at least
won't block forward progress on non-http2 functionality on Python 3.
hg log: solves bug regarding hg log -r 0:null (issue4039)

'hg log -r 0:null' was showing only one changeset(the '-1' one) instead of the first two changesets.

--HG--
branch : stable
commit: create new amend changeset as secret correctly for "--secret" option

Before this patch, "hg commit --amend --secret" doesn't create new
amend changeset as secret, even though the internal function
"commitfunc()" passed to "cmdutil.amend()" make "phases.new-commit"
configuration as "secret" temporarily.

"cmdutil.amend()" uses specified "commitfunc" only for temporary amend
commit, and creates the final amend commit changeset by
"localrepository.commitctx()" directly with memctx.

This patch creates new amend changeset as secret correctly for
"--secret" option, by changing "phases.new-commit" configuration
temporarily before "localrepository.commitctx()".

--HG--
branch : stable
merge with stable