Set solr config to have the same behaviour that SolrSearchConfig with multiple terme searching

Hello,

The solr search implementation on quicksearch feature, doesn't currently allow search result relevance to be dependant on word proximity (even after ben patch applied:https://github.com/xwiki/xwiki-platform/pull/617). This causes searches with multiple terms to have low precision.

See:  https://forum.xwiki.org/t/some-issue-with-solr-and-quicksearch-with-multiple-words/3549

Thxs.

Pascal