bug: 'health' command reference before assignment on Exception.

[bendemott]

ERROR RUNNING check_zookeeper_connectivity

Traceback (most recent call last):
File "C:\Python27\Scripts\solr-zkutil", line 13, in
sys.exit(main(sys.argv))
File "C:\Python27\lib\site-packages\solrzkutil_init_.py", line 1018, in main
health_check(zookeepers=args['zookeepers'])
File "C:\Python27\lib\site-packages\solrzkutil_init_.py", line 742, in health_check
if not errors:
UnboundLocalError: local variable 'errors' referenced before assignment