fix(logger): import syslog package from github

Since syslog.go is located at github.com/opdemand/deis/logger/syslog,
we should be imorting from there. Without this change, running
syslogd.go will complain that the syslog package does not exist.
Merge pull request #789 from opdemand/import-syslog

fix(logger): import syslog package from github