logtoprocess: clean-up old comment

The comment was likely to be for runshellcommand code.

Differential Revision: https://phab.mercurial-scm.org/D1425

hgext/logtoprocess.py

@@ -124,8 +124,6 b' def uisetup(ui):'
                 env = dict(itertools.chain(encoding.environ.items(),
                                            msgpairs, optpairs),
                            EVENT=event, HGPID=str(os.getpid()))
-                # Connect stdin to /dev/null to prevent child processes messing
-                # with mercurial's stdin.
                 runshellcommand(script, env)
             return super(logtoprocessui, self).log(event, *msg, **opts)