Restart rsyslog after creating /etc/rsyslog.d/11-swift.conf

Otherwise, the file is simply not used.
Fix detection of rsyslog version

The backslashes used in the sed command were lost (due to them being
seen as escape backslashes by ruby, I guess).
Merge pull request #260 from vuntz/restart-syslog

Restart rsyslog after creating /etc/rsyslog.d/11-swift.conf