(#293) Bugfix for path to pid in logrotate script

EL 6 uses syslog.pid instead of rsyslog.pid. This patch allows for the
path to the pid file to be specified as a parameter and has defaults for
all supported platforms.
Merge pull request #28 from ghoneycutt/293_fix_el6_logrotate_issue

(#293) Bugfix for path to pid in logrotate script

EL 6 uses syslog.pid instead of rsyslog.pid. This patch allows for the
path to the pid file to be specified as a parameter and has defaults for
all supported platforms.