fix #573 : Improve log messages of /var/log/message on CentOS7

src/packaging/common/systemd/fess.service

@@ -1,5 +1,5 @@
 [Unit]
-Description=Fess is very powerful and easily deployable Enterprise Search Server.
+Description=Fess
 Documentation=http://fess.codelibs.org/
 Wants=network-online.target
 After=network-online.target elasticsearch.service