incorrect chmod not reported by daemon

- Version: logstash-2.3.0-1.noarch
- Operating System: Centos 7
- Sample Data: see `log`
- Steps to Reproduce: be a bit dull
1. Create filter files
2. Create pattern and change filters to point to catalog with patterns
3. Start daemon
4. Get error that does not really tell you anything
5. Start in debug (works?!?)
6. Use 30 minutes to find out what the issue is
7. `facepalm`
8. chmod 644 /etc/logstash/pattern.d/*
9. Sucess!

Suggestion (since I do this more for others whom might have the same issue) please add some kind of check on the pattern folder (and config folder) so that files with paranoid chmods are noticed and complained about.

ls

```
/etc/logstash/conf.d
-rw-r--r--. 1 root root 3.2K Apr 21 10:37 00-inputs.conf
-rw-r--r--. 1 root root 830 Apr 21 12:23 01-transforms.conf
-rw-r--r--. 1 root root 176 Apr 21 10:32 99-outputs.conf

/etc/logstash/pattern.d
-rw-------. 1 root root 645 Apr 21 12:23 11-tomcat.pattern
```

log

```
{:timestamp=>"2016-04-21T12:17:46.842000+0200", :message=>"Pipeline aborted due to error", :exception=>#, :backtrace=>["/opt/logstash/vendor/bundle/jruby/1.9/gems/jls-grok-0.11.2/lib/grok-pure.rb:83:in `add_patterns_from_file'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-filter-multiline-2.0.5/lib/logstash/filters/multiline.rb:147:in `register'", "org/jruby/RubyArray.java:1613:in `each'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-filter-multiline-2.0.5/lib/logstash/filters/multiline.rb:145:in `register'", "org/jruby/RubyArray.java:1613:in `each'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-filter-multiline-2.0.5/lib/logstash/filters/multiline.rb:143:in `register'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.0-java/lib/logstash/pipeline.rb:186:in `start_workers'", "org/jruby/RubyArray.java:1613:in `each'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.0-java/lib/logstash/pipeline.rb:186:in `start_workers'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.0-java/lib/logstash/pipeline.rb:140:in `run'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.0-java/lib/logstash/agent.rb:448:in `start_pipeline'"], :level=>:error}
{:timestamp=>"2016-04-21T12:17:49.852000+0200", :message=>"stopping pipeline", :id=>"main"}
```