mercurial.el: ignore errors on hg-after-save-hook()
Don't signal an error even if running hg command fails. Otherwise,
succeeding hooks won't be called.
#!/bin/sh
hg init test
cd test
echo % Without -v
hg serve -a localhost -p 20063 -d --pid-file=hg.pid
cat hg.pid >> "$DAEMON_PIDS"
echo % With -v
hg serve -a localhost -p 20064 -d --pid-file=hg.pid -v
cat hg.pid >> "$DAEMON_PIDS"