tests: use killdaemons in hgweb tests
hgweb tests often failed on my system because the serve port wasn't free when a
new hgweb was started; the killed hg wasn't completely dead yet.
Now we use killdaemons which waits for the process to die.
% create source repository
adding a
% fork source repository
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding b
% update source repository
% merge repositories
pulling from ../t2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
M b
% rename b as c
A c
R b
% rename back c as b
M b