serve: simply return instead of calling sys.exit() in `hg serve --stdio`
The shouldn't be a reason to call `sys.exit()` instead of letting the
code return normally. I've remove the call in both `hg serve` and `hg
debugserve`.
Differential Revision: https://phab.mercurial-scm.org/D9271
$ hg init r1
$ cd r1
$ hg ci --config ui.allowemptycommit=true -m c0
$ hg ci --config ui.allowemptycommit=true -m c1
$ hg ci --config ui.allowemptycommit=true -m c2
$ hg co -q 0
$ hg ci --config ui.allowemptycommit=true -m c3
created new head
$ hg co -q 3
$ hg merge --quiet
$ hg ci --config ui.allowemptycommit=true -m c4
$ hg log -G -T'{desc}'
@ c4
|\
| o c3
| |
o | c2
| |
o | c1
|/
o c0
>>> from mercurial import hg
>>> from mercurial import ui as uimod
>>> repo = hg.repository(uimod.ui())
>>> for anc in repo.changelog.ancestors([4], inclusive=True):
... print(anc)
4
3
2
1
0