Confirmed this breaks `drip` usage:

```
# With this patch (#1189)
% USE_JRUBY=1 JAVACMD=drip bin/logstash version
Could not find any executable java binary. Please install java in your PATH or set JAVA_HOME.

# Without this patch:
% USE_JRUBY=1 JAVACMD=drip bin/logstash version
logstash 1.4.0
```
```