bin/solr -h should print generic help

Typing only:

bin/solr

...prints the generic tool help, but if you add a -h

bin/solr -h

...you get an error message and the help for the start command. In fact, any unknown parameter given, such as bin/solr -foo will assume start.

This is confusing, since -h is a common help option. Could check for the special case where there is only the -h switch given, in which case we should not assume the intention is to do start but to get help.