Syntax error, unexpected $end, expecting EOL

```
root@app3:~# service stackdriver-agent restart
 * Restarting Stackdriver metrics collection agent stackdriver-agent                                                                                                                           Parse error in file `/opt/stackdriver/collectd/etc/collectd.d/nginx.conf', line 69 near `': syntax error, unexpected $end, expecting EOL
yyparse returned error #1
configfile: Cannot read file `/opt/stackdriver/collectd/etc/collectd.d/nginx.conf'.
option = Hostname; value = test1;
option = Interval; value = 60.000000;
Created new plugin context.
Parse error in file `/opt/stackdriver/collectd/etc/collectd.d/nginx.conf', line 69 near `': syntax error, unexpected $end, expecting EOL
yyparse returned error #1
configfile: Cannot read file `/opt/stackdriver/collectd/etc/collectd.d/nginx.conf'.
option = Hostname; value = test1;
option = Interval; value = 60.000000;
Created new plugin context.
option = PIDFile; value = /var/run/stackdriver-agent.pid;
Parse error in file `/opt/stackdriver/collectd/etc/collectd.d/nginx.conf', line 69 near `': syntax error, unexpected $end, expecting EOL
yyparse returned error #1
configfile: Cannot read file `/opt/stackdriver/collectd/etc/collectd.d/nginx.conf'.
option = Hostname; value = test1;
option = Interval; value = 60.000000;
Created new plugin context.
```