codereview: abort 'hg commit' before entering commit message.

Hook pre-commit runs before 'hg commit' command whereas hook precommit runs
after the user has entered commit message.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/106320043

lib/codereview/codereview.py

@@ -2289,6 +2289,10 @@ codereview_init = False
 def uisetup(ui):
 	global testing
 	testing = ui.config("codereview", "testing")
+	# Disable the Mercurial commands that might change the repository.
+	# Only commands in this extension are supposed to do that.
+	ui.setconfig("hooks", "pre-commit.codereview", precommithook) # runs before 'hg commit'
+	ui.setconfig("hooks", "precommit.codereview", precommithook) # catches all cases
 
 def reposetup(ui, repo):
 	global codereview_disabled
@@ -2338,10 +2342,6 @@ def reposetup(ui, repo):
 	InstallMatch(ui, repo)
 	RietveldSetup(ui, repo)
 
-	# Disable the Mercurial commands that might change the repository.
-	# Only commands in this extension are supposed to do that.
-	ui.setconfig("hooks", "precommit.codereview", precommithook)
-
 	# Rollback removes an existing commit.  Don't do that either.
 	global real_rollback
 	real_rollback = repo.rollback