Update solr5 generator solr_wrapper require.

[grosscol]

Avoid requiring solr_wrapper in production environment as the gem will not be installed.

[jcoyne]

This seems reasonable. We never had this problem with jettywrapper because we put it in the root of the gemfile rather than the :development and :test groups.

[coveralls]

Coverage remained the same at 77.043% when pulling 621b293 on grosscol:patch-1 into 6073f6c on projectblacklight:master.